Granit o'zining o'ta mustahkamligi, zichligi, chidamliligi va korroziyaga chidamliligi uchun qazib olinadigan magmatik tog 'jinsining bir turidir. Ammo granit ham juda ko'p qirrali - u nafaqat kvadrat va to'rtburchaklar uchun! Darhaqiqat, biz muntazam ravishda barcha o'zgarishlarning shakllari, burchaklari va egri chiziqlarida ishlab chiqarilgan granit komponentlari bilan ishonchli ishlaymiz va ajoyib natijalarga erishamiz.
Through our state of the art processing, cut surfaces can be exceptionally flat. These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components. Granite is:
■ ishlov beriladigan
■ kesilgan va tugatilganda aniq tekis
■ zangga chidamli
■ bardoshli
■ uzoq muddatli
Granit komponentlarini tozalash ham oson. Maxsus dizaynlarni yaratishda, uning ustun afzalliklari uchun granitni tanlashga ishonch hosil qiling.

STANDARTLAR / YUQORI KIYIMGA CHIDAMLI QO'LLANMALAR
ZHHIMG tomonidan standart sirt plitalari mahsulotlari uchun ishlatiladigan granit yuqori kvarts tarkibiga ega, bu esa aşınma va shikastlanishga nisbatan yuqori qarshilikni ta'minlaydi. Bizning Superior Black ranglarimiz suvni yutish darajasi past, bu sizning aniqlik o'lchagichlaringiz plitalarga o'rnatilganda zanglash ehtimolini kamaytiradi. ZHHIMG tomonidan taqdim etiladigan granit ranglari kamroq porlashga olib keladi, bu esa plitalardan foydalanayotgan odamlar uchun ko'zning charchashini kamaytiradi. Biz bu jihatni minimal darajada ushlab turish uchun issiqlik kengayishini hisobga olgan holda granit turlarini tanladik.

CUSTOM APPLICATIONS
Agar sizning arizangiz maxsus shakllar, tishli qo'shimchalar, uyalar yoki boshqa ishlov berish usullariga ega plastinka talab qilsa, siz Black Jinan Black kabi materialni tanlashingiz kerak bo'ladi. Ushbu tabiiy material yuqori qattiqlik, ajoyib tebranishlarni susaytiruvchi va yaxshilangan ishlov berish qobiliyatini ta'minlaydi.

Shuni ta'kidlash kerakki, rangning o'zi toshning jismoniy xususiyatlarining ko'rsatkichi emas. Umuman olganda, granitning rangi minerallarning mavjudligi yoki yo'qligi bilan bevosita bog'liq bo'lib, bu yaxshi sirt plastinka materialini tashkil etuvchi xususiyatlarga hech qanday ta'sir ko'rsatmasligi mumkin. Sirt plitalari uchun juda mos keladigan pushti, kulrang va qora granitlar, shuningdek, aniq qo'llanilish uchun mutlaqo yaroqsiz bo'lgan qora, kulrang va pushti granitlar mavjud. Granitning sirt plastinka materiali sifatida ishlatilishiga oid muhim xususiyatlari rang bilan hech qanday aloqasi yo'q va quyidagilar:
■ Qattiqlik (yuk ostida og'ish - Elastiklik moduli bilan ko'rsatilgan)
■ Qattiqlik
■ Zichlik
■ Aşınma qarshiligi
■ Barqarorlik
■ G'ovaklik

Biz ko'plab granit materiallarini sinovdan o'tkazdik va bu materiallarni taqqosladik. Nihoyat, natijaga erishdik, Jinan qora graniti biz bilgan eng yaxshi materialdir. Hind qora graniti va Janubiy Afrika graniti Jinan qora granitiga o'xshash, ammo ularning fizik xususiyatlari Jinan qora granitidan kamroq. ZHHIMG dunyoda ko'proq granit materiallarini qidirishda davom etadi va ularning fizik xususiyatlarini taqqoslaydi.

Loyihangiz uchun mos granit haqida ko'proq ma'lumot olish uchun biz bilan bog'laninginfo@zhhimg.com.

Turli ishlab chiqaruvchilar turli xil standartlardan foydalanadilar. Dunyoda ko'plab standartlar mavjud.
DIN standarti, ASME B89.3.7-2013 yoki Federal spetsifikatsiya GGG-P-463c (Granit sirt plitalari) va boshqalar ularning texnik xususiyatlari uchun asos sifatida.

Va biz sizning talablaringizga muvofiq granit aniqlikdagi tekshirish plitasini ishlab chiqarishimiz mumkin. Agar siz ko'proq standartlar haqida ko'proq ma'lumotga ega bo'lishni istasangiz, biz bilan bog'lanishga xush kelibsiz.

Tekislik deganda sirtdagi barcha nuqtalarning ikkita parallel tekislik, asos tekisligi va tom tekisligi ichida joylashganligi tushuniladi. Tekisliklar orasidagi masofani o'lchash sirtning umumiy tekisligini anglatadi. Bu tekislik o'lchovi odatda tolerantlikka ega va darajani belgilashni o'z ichiga olishi mumkin.

Masalan, uchta standart sinf uchun tekislik bardoshliligi federal spetsifikatsiyada quyidagi formula bilan aniqlanganidek belgilanadi:
■ Laboratoriya darajasi AA = (40 + diagonal kvadrat/25) x .000001" (bir tomonlama)
■ Tekshirish darajasi A = Laboratoriya darajasi AA x 2
■ Asboblar xonasi B darajasi = Laboratoriya darajasi AA x 4.

Standart o'lchamdagi sirt plitalari uchun biz ushbu spetsifikatsiya talablaridan oshib ketadigan tekislik bardoshliligini kafolatlaymiz. Tekislikdan tashqari, ASME B89.3.7-2013 va Federal Spetsifikatsiya GGG-P-463c quyidagi mavzularni qamrab oladi: takroriy o'lchov aniqligi, sirt plastinka granitlarining material xususiyatlari, sirt qoplamasi, tayanch nuqtasining joylashuvi, qattiqlik, tekshirishning maqbul usullari, tishli qo'shimchalarni o'rnatish va boshqalar.

ZHHIMG granit sirt plitalari va granit tekshirish plitalari ushbu spetsifikatsiyada ko'rsatilgan barcha talablarga javob beradi yoki ulardan oshib ketadi. Hozirgi vaqtda granit burchak plitalari, parallelliklar yoki asosiy kvadratlar uchun aniq spetsifikatsiya mavjud emas.

Va siz boshqa standartlar uchun formulalarni topishingiz mumkinYUKLAB OLING.

Birinchidan, plastinkani toza saqlash muhimdir. Havoda tarqaladigan abraziv chang odatda plastinkaning eng katta aşınma va yirtilish manbai hisoblanadi, chunki u ish qismlariga va o'lchagichlarning aloqa yuzalariga singib ketadi. Ikkinchidan, plastinkani chang va shikastlanishdan himoya qilish uchun uni yoping. Ishlatilmayotganda plastinkani yopib qo'yish, plastinkani vaqti-vaqti bilan aylantirish orqali, bitta joy ortiqcha ishlatilmasligi uchun va o'lchagichdagi po'lat aloqa yostiqchalarini karbid yostiqchalari bilan almashtirish orqali aşınma muddatini uzaytirish mumkin. Shuningdek, plastinkaga ovqat yoki alkogolsiz ichimliklarni qo'yishdan saqlaning. E'tibor bering, ko'plab alkogolsiz ichimliklar tarkibida uglerod yoki fosfor kislotasi mavjud bo'lib, ular yumshoqroq minerallarni eritib, yuzasida kichik chuqurchalar qoldirishi mumkin.

Bu likopcha qanday ishlatilayotganiga bog'liq. Iloji bo'lsa, likopchani kunning boshida (yoki ish smenasida) va oxirida tozalashni tavsiya qilamiz. Agar likopcha ifloslansa, ayniqsa yog'li yoki yopishqoq suyuqliklar bilan ifloslansa, uni darhol tozalash kerak.

Plastinani muntazam ravishda suyuq yoki ZHHIMG suvsiz sirt plastinka tozalagichi bilan tozalang. Tozalash eritmalarini tanlash muhim ahamiyatga ega. Agar uchuvchan erituvchi (atseton, lak erituvchisi, spirt va boshqalar) ishlatilsa, bug'lanish sirtni sovutadi va uni buzadi. Bunday holda, ishlatishdan oldin plitaning normallashishiga imkon berish kerak, aks holda o'lchov xatolari yuzaga keladi.

Plastinkaning normallashishi uchun zarur bo'lgan vaqt plastinkaning o'lchamiga va sovutish miqdoriga qarab o'zgaradi. Kichikroq plitalar uchun bir soat yetarli bo'lishi kerak. Kattaroq plitalar uchun ikki soat kerak bo'lishi mumkin. Agar suvga asoslangan tozalagich ishlatilsa, bug'lanish orqali sovutish ham bo'ladi.

Plastinka suvni ham ushlab qoladi va bu sirt bilan aloqa qilgan metall qismlarning zanglashiga olib kelishi mumkin. Ba'zi tozalagichlar quriganidan keyin yopishqoq qoldiq qoldiradi, bu esa havodagi changni o'ziga tortadi va aslida aşınmayı kamaytiradi, balki oshiradi.

Bu plastinkadan foydalanish va atrof-muhitga bog'liq. Biz yangi plastinka yoki aniq granit aksessuarini sotib olinganidan keyin bir yil ichida to'liq qayta kalibrlashni tavsiya qilamiz. Agar granit sirt plitasi ko'p ishlatilsa, bu vaqt oralig'ini olti oygacha qisqartirish tavsiya etiladi. Elektron sath yoki shunga o'xshash qurilma yordamida takroriy o'lchov xatolarini oylik tekshirish har qanday rivojlanayotgan aşınma joylarini ko'rsatadi va uni bajarish uchun bir necha daqiqa vaqt ketadi. Birinchi qayta kalibrlash natijalari aniqlangandan so'ng, kalibrlash oralig'i sizning ichki sifat tizimingiz tomonidan ruxsat etilganidek yoki talab qilinganidek uzaytirilishi yoki qisqartirilishi mumkin.

Biz sizga granit sirt plitangizni tekshirish va kalibrlashda yordam beradigan xizmatni taklif qila olamiz.

Kalibrlashlar orasidagi farqlarning bir nechta sabablari bo'lishi mumkin:

• Kalibrlashdan oldin sirt issiq yoki sovuq eritma bilan yuvilgan va normalizatsiya qilish uchun yetarli vaqt berilmagan.
• Plastinka noto'g'ri qo'llab-quvvatlangan
• Harorat o'zgarishi
• Qoralamalar
• Plitaning yuzasiga to'g'ridan-to'g'ri quyosh nuri yoki boshqa issiqlik nurlari tushsin. Yuqoridan tushadigan yorug'lik sirtni isitmasligiga ishonch hosil qiling
• Qish va yoz o'rtasidagi vertikal harorat gradientidagi o'zgarishlar (Iloji bo'lsa, kalibrlash amalga oshirilgan paytdagi vertikal gradient haroratini biling.)
• Yuk tashishdan keyin plastinka normallashishi uchun yetarli vaqt berilmagan
• Tekshirish uskunasidan noto'g'ri foydalanish yoki kalibrlanmagan uskunadan foydalanish
• Aşınma natijasida yuzaga keladigan sirt o'zgarishi

Aniq granitda nechta turdagi teshiklar mavjud?

Precision Granit komponentlaridagi uyalar

Ko'pgina fabrikalar, tekshirish xonalari va laboratoriyalar uchun aniq o'lchovlar uchun asos sifatida aniq granit sirt plitalari tayaniladi. Har bir chiziqli o'lchov yakuniy o'lchamlar olinadigan aniq mos yozuvlar yuzasiga bog'liq bo'lgani uchun, sirt plitalari ishlov berishdan oldin ishlarni tekshirish va joylashtirish uchun eng yaxshi mos yozuvlar tekisligini ta'minlaydi. Ular, shuningdek, balandlik o'lchovlarini va o'lchov sirtlarini o'lchash uchun ideal asosdir. Bundan tashqari, yuqori darajadagi tekislik, barqarorlik, umumiy sifat va mahorat ularni murakkab mexanik, elektron va optik o'lchash tizimlarini o'rnatish uchun yaxshi tanlovga aylantiradi. Ushbu o'lchash jarayonlarining har biri uchun sirt plitalarini kalibrlangan holda saqlash juda muhimdir.

Repeat Measurements and Flatness

Aniq sirtni ta'minlash uchun ham tekislik, ham takroriy o'lchovlar juda muhimdir. Tekislik deganda sirtdagi barcha nuqtalarning ikkita parallel tekislik, asos tekisligi va tom tekisligi ichida joylashganligi tushuniladi. Tekisliklar orasidagi masofani o'lchash sirtning umumiy tekisligi hisoblanadi. Bu tekislik o'lchovi odatda tolerantlikka ega va darajani belgilashni o'z ichiga olishi mumkin.

The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula:

DIN standarti, GB standarti, ASME standarti, JJS standarti... turli mamlakatlarda turli stendlar mavjud...

Standart haqida batafsil ma'lumot.

In addition to flatness, repeatability must be ensured. A repeat measurement is a measurement of local flatness areas. It is a measurement taken anywhere on the surface of a plate that will repeat within the stated tolerance. Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.

Sirt plitasining ham tekislik, ham takroriy o'lchov talablariga javob berishini ta'minlash uchun granit sirt plitalari ishlab chiqaruvchilari o'z talablari uchun asos sifatida GGG-P-463c Federal Specification dan foydalanishlari kerak. Ushbu standart takroriy o'lchov aniqligi, sirt plitasi granitining material xususiyatlari, sirt qoplamasi, tayanch nuqtasining joylashuvi, qattiqligi, rezbali qo'shimchalarni tekshirishning maqbul usullari va o'rnatishni ko'rib chiqadi.

Checking Plate Accuracy

Bir nechta oddiy ko'rsatmalarga amal qilish orqali granit sirt plitasiga investitsiya ko'p yillarga yetishi kerak. Plitadan foydalanishga, ustaxona muhitiga va talab qilinadigan aniqlikka qarab, sirt plitasining aniqligini tekshirish chastotasi har xil bo'ladi. Umumiy qoida shundaki, yangi plita sotib olinganidan keyin bir yil ichida to'liq qayta kalibrlanishi kerak. Agar plita tez-tez ishlatilsa, bu vaqt oralig'ini olti oygacha qisqartirish tavsiya etiladi.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

An effective inspection program should include regular checks with an autocollimator, providing actual calibration of overall flatness traceable to National Institute of Standards and Technology (NIST). Comprehensive calibration by the manufacturer or an independent company is necessary from time to time.

Variations Between Calibrations

Ba'zi hollarda, sirt plitalarini kalibrlash o'rtasida farqlar mavjud. Ba'zan bu o'zgarishlarni aşınma natijasida yuzaga keladigan sirt o'zgarishi, tekshirish uskunalaridan noto'g'ri foydalanish yoki kalibrlanmagan uskunalardan foydalanish kabi omillar tushuntirishi mumkin. Biroq, eng keng tarqalgan ikkita omil harorat va qo'llab-quvvatlashdir.

One of the most important variables is temperature. For instance, the surface might have been washed with a hot or cold solution prior to calibration and not allowed sufficient time to normalize. Other causes of temperature change include drafts of cold or hot air, direct sunlight, overhead lighting or other sources of radiant heat on the surface of the plate.

There also can be variations in the vertical temperature gradient between winter and summer. In some cases, the plate is not allowed sufficient time to normalize after shipment. It is a good idea to record the vertical gradient temperature at the time the calibration is performed.

Another common cause for calibration variation is a plate that is improperly supported. A surface plate should be supported at three points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered.

Only three points can rest solidly on anything but a precision surface. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same three points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. Consider using steel stands with support beams designed to line up with the proper support points. Stands for this purpose are generally available from the surface plate manufacturer.

If the plate is properly supported, precise leveling is only necessary if an application specifies it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

Extend Plate Life

Bir nechta ko'rsatmalarga rioya qilish granit sirt plitasining aşınmasını kamaytiradi va oxir-oqibat uning ishlash muddatini uzaytiradi.

Birinchidan, plastinkani toza saqlash muhimdir. Havoda tarqaladigan abraziv chang odatda plastinkada eng katta aşınma va yirtilish manbai hisoblanadi, chunki u ish qismlariga va o'lchagichlarning aloqa yuzalariga singib ketishga moyil.

It also is important to cover plates to protect it from dust and damage. Wear life can be extended by covering the plate when not in use.

Plastinkani vaqti-vaqti bilan aylantiring, shunda bitta joy ortiqcha ishlatilmaydi. Shuningdek, o'lchash moslamalaridagi po'lat kontakt prokladkalarini karbid prokladkalari bilan almashtirish tavsiya etiladi.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

Where to Relap

Granit sirt plitasini qayta qoplash kerak bo'lganda, ushbu xizmatni joyida yoki kalibrlash zavodida bajarishni ko'rib chiqing. Plitani zavodda yoki maxsus zavodda qayta qoplash har doim afzalroqdir. Biroq, agar plastinka juda yomon eskirmagan bo'lsa, odatda kerakli tolerantlikdan 0,001 dyuym ichida bo'lsa, uni joyida qayta qoplash mumkin. Agar plastinka tolerantlikdan 0,001 dyuymdan ortiq bo'lgan darajada eskirgan bo'lsa yoki u yomon chuqurchaga yoki tirnalishga uchragan bo'lsa, uni qayta qoplashdan oldin maydalash uchun zavodga yuborish kerak.

A calibration facility has the equipment and factory setting providing the optimum conditions for proper plate calibration and rework if necessary.

Joyida kalibrlash va qayta qoplama bo'yicha mutaxassisni tanlashda juda ehtiyot bo'lish kerak. Akkreditatsiya so'rang va texnik foydalanadigan uskunaning kuzatilishi mumkin bo'lgan kalibrlash xususiyatiga ega ekanligini tekshiring. Tajriba ham muhim omil hisoblanadi, chunki aniq granitni qanday qilib to'g'ri tekislashni o'rganish uchun ko'p yillar kerak bo'ladi.

Critical measurements start with a precision granite surface plate as a baseline. By ensuring a reliable reference by using a properly calibrated surface plate, manufacturers have one of the essential tools for reliable measurements and better quality parts.Q

Checklist for Calibration Variations

1. Sirt kalibrlashdan oldin issiq yoki sovuq eritma bilan yuvilgan va normalizatsiya qilish uchun yetarli vaqt berilmagan.

2. Plastinka noto'g'ri qo'llab-quvvatlangan.

3. Harorat o'zgarishi.

4. Qoralamalar.

5. Plitaning yuzasiga to'g'ridan-to'g'ri quyosh nuri yoki boshqa issiqlik nurlari tushmasin. Yuqoridan tushadigan yorug'lik sirtni isitmasligiga ishonch hosil qiling.

6. Qish va yoz o'rtasidagi vertikal harorat gradientidagi o'zgarishlar. Iloji bo'lsa, kalibrlash amalga oshirilgan paytdagi vertikal gradient haroratini biling.

7. Plastinka jo'natilgandan keyin normallashishi uchun yetarli vaqt berilmagan.

8. Tekshirish uskunasidan noto'g'ri foydalanish yoki kalibrlanmagan uskunadan foydalanish.

9. Aşınma natijasida yuzaga keladigan sirt o'zgarishi.

Tech Tips

• Har bir chiziqli o'lchov yakuniy o'lchamlar olinadigan aniq mos yozuvlar yuzasiga bog'liq bo'lgani uchun, sirt plitalari ishlov berishdan oldin ishlarni tekshirish va joylashtirish uchun eng yaxshi mos yozuvlar tekisligini ta'minlaydi.
• Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.
• Samarali tekshirish dasturi avtokollimator bilan muntazam tekshiruvlarni o'z ichiga olishi kerak, bu esa Milliy inspeksiya organi tomonidan kuzatilishi mumkin bo'lgan umumiy tekislikni haqiqiy kalibrlashni ta'minlaydi.

Granitni tashkil etuvchi mineral zarrachalar orasida 90% dan ortig'i dala shpati va kvarts bo'lib, ulardan dala shpati eng ko'p uchraydi. Dala shpati ko'pincha oq, kulrang va qizil rangda bo'ladi va kvarts asosan rangsiz yoki kulrang oq rangda bo'lib, ular granitning asosiy rangini tashkil qiladi. Dala shpati va kvarts qattiq minerallar bo'lib, ularni po'lat pichoq bilan siljitish qiyin. Granitdagi qora dog'lar, asosan qora slyuda, boshqa ba'zi minerallar ham mavjud. Biotit nisbatan yumshoq bo'lsa-da, uning stressga qarshi turish qobiliyati zaif emas va shu bilan birga ularda granitning oz miqdori, ko'pincha 10% dan kam. Bu granit ayniqsa kuchli bo'lgan material holatidir.

Granitning mustahkamligining yana bir sababi shundaki, uning mineral zarralari bir-biriga mahkam bog'langan va bir-biriga singib ketgan. G'ovaklar ko'pincha tog 'jinsining umumiy hajmining 1% dan kamrog'ini tashkil qiladi. Bu granitga kuchli bosimga bardosh berish qobiliyatini beradi va namlik bilan osongina o'tib ketmaydi.

Granit komponentlari zanglamaydigan, kislota va ishqorga chidamli, yaxshi aşınmaya bardoshli va uzoq xizmat muddatiga ega toshdan yasalgan, maxsus parvarish talab etilmaydi. Granit aniqlik komponentlari asosan mashinasozlik sanoatida asbobsozlikda qo'llaniladi. Shuning uchun ular granit aniqlik komponentlari yoki granit komponentlari deb ataladi. Granit aniqlik komponentlarining xususiyatlari asosan granit platformalarinikiga o'xshash. Granit aniqlik komponentlarini asbobsozlik va o'lchashga kirish: Aniq ishlov berish va mikro ishlov berish texnologiyasi mashinasozlik sanoatining muhim rivojlanish yo'nalishlari bo'lib, ular yuqori texnologiyali darajani o'lchash uchun muhim ko'rsatkichga aylandi. Zamonaviy texnologiyalar va mudofaa sanoatining rivojlanishi aniq ishlov berish va mikro ishlov berish texnologiyasidan ajralmasdir. Granit komponentlari o'lchovda silliq siljiydi, turg'unliksiz. Ish yuzasini o'lchash, umumiy tirnalishlar o'lchov aniqligiga ta'sir qilmaydi. Granit komponentlari talab tomonining talablariga muvofiq ishlab chiqilishi va ishlab chiqarilishi kerak.

Qo'llash maydoni:

Barchamizga ma'lumki, tobora ko'proq mashina va uskunalar aniq granit komponentlarini tanlamoqda.

Granit komponentlari dinamik harakat, chiziqli motorlar, cmm, cnc, lazer mashinasi uchun ishlatiladi...

Qo'shimcha ma'lumot olish uchun biz bilan bog'lanishga xush kelibsiz.

Granit o'lchash moslamalari va granit mexanik komponentlari yuqori sifatli Jinan Black granitidan tayyorlangan. Yuqori aniqlik, uzoq umr, yaxshi barqarorlik va korroziyaga chidamliligi tufayli ular zamonaviy sanoat mahsulotlarini tekshirishda va mexanik aviatsiya va ilmiy tadqiqotlar kabi ilmiy sohalarda tobora ko'proq qo'llanila boshlandi.

Afzalliklari

----Chuyan temirdan ikki baravar qattiqroq;

----O'lchamdagi minimal o'zgarishlar harorat o'zgarishi bilan bog'liq;

----Siqilishdan xoli, shuning uchun ishda uzilish bo'lmaydi;

----Mayda donador tuzilish va ozgina yopishqoqlik tufayli burmalar yoki chiqib ketishlar yo'q, bu uzoq xizmat muddati davomida yuqori darajadagi tekislikni ta'minlaydi va boshqa qismlarga yoki asboblarga zarar yetkazmaydi;

---- Magnit materiallar bilan ishlash uchun muammosiz ishlash;

---- Uzoq umr va zanglamaydi, natijada texnik xizmat ko'rsatish xarajatlari past bo'ladi.

Aniq granit sirt plitalari aniqlikka erishish uchun yuqori tekislik standartiga qadar aniqlik bilan qoplangan va murakkab mexanik, elektron va optik o'lchash tizimlarini o'rnatish uchun asos sifatida ishlatiladi.

Granit sirt plitasining ba'zi o'ziga xos xususiyatlari:

Qattiqlikdagi bir xillik;

Yuk ostida aniq sharoitlar;

Vibratsiyani yutuvchi;

Tozalash oson;

O'rashga chidamli;

Past g'ovaklilik;

Aşındırıcı bo'lmagan;

Magnit bo'lmagan

Granit sirt plitasining afzalliklari

First, the rock after a long period of natural aging, uniform structure, coefficient minimum, the internal stress completely disappear, not deformed, so the precision is high.

Elektron pochta xabarini yuborish

Whatsapp

Skype

Inglizcha

Nemischa

Fransuzcha

Portugalcha

Ispancha

Yaponcha

Koreyscha

Arabcha

Irlandcha

Yunoncha

Turkcha

Italiyacha

Daniyacha

Rumincha

Indonez tili

Chexcha

Shvedcha

Polsha

Baskcha

Katalancha

Esperanto

Hind tili

Laoscha

Albancha

Amharcha

Armancha

Ozarbayjon

Belaruscha

PBengal tili

Bosniya

Bolgarcha

Sebuancha

Chicheva

Korsikalik

Xorvatcha

Gollandiyalik

Estoncha

Filippincha

Fincha

Frizcha

Galisiyalik

Gruzincha

Gujarati

Gaiticha

Xausa

GavayiIbroniychaHmong

VengerchaIslandchaIgbo

YavachaKannada

Qozoqcha

Khmer

Kurdcha

Qirg'iz

Lotin tili

Latviyacha

Litvacha

Lyuksemburg..

Makedoniyalik

Malagasi

Malaycha

Malayalam

Maltacha

Maori

Marathi

Mo'g'ulcha

Birmacha

Nepalcha

Norvegcha

Pashto

Forscha

Panjobcha

Serbcha

Sesotho

Sinhala

Slovakcha

1. Slovencha

1. Somalicha
2. Samoa
3. Shotlandiya Gael tili
4. Shona
5. Sindhi
6. Sundancha
7. Suaxili tili
8. Tojikcha
9. Tamilcha
10. Telugu

Taylandcha

Ukraina

UrduchaAO'zbekcha2VetnamchaLUelslikAXosacha

Yidishcha

Yoruba

Zulu

Kinyarvanda

Tatarcha

Precision Granite Base Can Improve Machine Tool Performances

Requirements are constantly increasing in mechanical engineering in general and in machine tool construction in particular. Achieving maximum precision and performance values without increasing costs are constant challenges to being competitive. The machine tool bed is a decisive factor here. Therefore, more and more machine tool manufacturers are relying on granite. Due to its physical parameters, it offers clear advantages that cannot be achieved with steel or polymer concrete.

Granite is a so-called volcanic deep rock and has a very dense and homogeneous structure with an extremely low coefficient of expansion, low thermal conductivity and high vibration damping.

Below you will discover why the common opinion that granite is mainly only suitable as machine base for high-end coordinate measuring machines is long outdated and why this natural material as a machine tool base is a very advantageous alternative to steel or cast iron even for high-precision machine tools.

We can manufacture granite components for dynamic motion, granite components for linear motors, granite components for ndt, granite components for xray, granite components for cmm, granite components for cnc, granite precision for laser, granite components for aerospace, granite components for precision stages...

High Added Value Without Additional Costs
The increasing use of granite in mechanical engineering is not so much due to the massive increase in the price of steel. Rather, it is because the added value for the machine tool achieved with a machine bed made of granite is possible at very little or no extra cost. This is proven by cost comparisons of well-known machine tool manufacturers in Germany and Europe.

The considerable gain in thermodynamic stability, vibration damping and long-term precision made possible by granite cannot be achieved with a cast iron or steel bed, or only at relatively high cost. For example, thermal errors can account for up to 75% of the total error of a machine, with compensation often attempted for by software – with moderate success. Due to its low thermal conductivity, granite is the better foundation for long-term precision.

With a tolerance of 1 μm, granite easily meets the flatness requirements according to DIN 876 for the degree of accuracy 00. With a value of 6 on the hardness scale 1 to 10, it is extremely hard, and with its specific weight of 2.8g/cm³ it almost reaches the value of aluminium. This also results in additional advantages such as higher feed rates, higher axis accelerations and an extension of the tool life for cutting machine tools. Thus, the change from a cast bed to a granite machine bed moves the machine tool in question into the high-end class in terms of precision and performance – at no extra cost.

Granite’s Improved Ecological Footprint
In contrast to materials such as steel or cast iron, natural stone does not have to be produced with a great deal of energy and using additives. Only relatively small amounts of energy are required for quarrying and surface treatment. This results in a superior ecological footprint, which even at the end of a machine’s life surpasses that of steel as a material. The granite bed can be the basis for a new machine or be used for completely different purposes such as shredding for road construction.

Nor are there any shortages of resources for granite. It is a deep rock formed from magma within the earth’s crust. It has ‘matured’ for millions of years and is available in very large quantities as a natural resource on almost all continents, including all of Europe.

Conclusion: The numerous demonstrable advantages of granite compared to steel or cast iron justify the increasing willingness of mechanical engineers to use this natural material as a foundation for high-precision, high-performance machine tools. Detailed information about granite properties, which are advantageous for machine tools and mechanical engineering, can be found in this further article.

A repeat measurement is a measurement of local flatness areas. The Repeat Measurement specification states that a measurement taken anywhere on the surface of a plate will repeat within the stated tolerance. Controlling local area flatness tighter than overall flatness guarantees a gradual change in surface flatness profile thereby minimizing local errors.

Most manufacturers, including imported brands, adhere to the Federal Specification of overall flatness tolerances but many overlook the repeat measurements. Many of the low value or budget plates available in the market today will not guarantee repeat measurements. A manufacturer who does not guarantee repeat measurements is NOT producing plates that meet the requirements of ASME B89.3.7-2013 or Federal Specification GGG-P-463c, or DIN 876, GB, JJS...

Both are critical to ensure a precision surface for accurate measurements. Flatness specification alone is not sufficient to guarantee measurement accuracy. Take as an example, a 36 X 48 Inspection Grade A surface plate, which meets ONLY the flatness specification of .000300". If the piece being checked bridges several peaks, and the gage being used is in a low spot, the measurement error could be the full tolerance in one area, 000300"! Actually, it can be much higher if the gage is resting on the slope of an incline.

Errors of .000600"-.000800" are possible, depending upon the severity of the slope, and the arm length of the gage being used. If this plate had a Repeat Measurement specification of .000050"F.I.R. then the measurement error would be less than .000050" regardless of where the measurement is taken on the plate. Another problem, which usually arises when an untrained technician attempts to resurface a plate on-site, is the use of Repeat Measurements alone to certify a plate.

The instruments that are used to verify repeatability are NOT designed to check overall flatness. When set to zero on a perfectly curved surface, they will continue to read zero, whether that surface is perfectly flat or perfectly concave or convex 1/2"! They simply verify the uniformity of the surface, not the flatness. Only a plate that meets both the flatness specification AND the repeat measurement specification truly meets the requirements of ASME B89.3.7-2013  or Federal Specification GGG-P-463c.

Ask us about or flatness specification and repeat measurement promise by calling +86 19969991659 or emailing INFO@ZHHIMG.COM

Yes, but they can only be guaranteed for a specific vertical temperature gradient. The effects of thermal expansion on the plate could easily cause a change in accuracy greater than the tolerance if there is a change in the gradient. In some cases, if the tolerance is tight enough, the heat absorbed from overhead lighting can cause enough of a gradient change over several hours.

Granite has a coefficient of thermal expansion of approximately .0000035 inches per inch per 1°F. As an example: A 36" x 48" x 8" surface plate has an accuracy of .000075" (1/2 of Grade AA) at a gradient of 0°F, the top and bottom are the same temperature. If the top of the plate warms up to the point where it is 1°F warmer than the bottom, the accuracy would change to .000275" convex ! Therefore, ordering a plate with a tolerance tighter than Laboratory Grade AA should only be considered if there is adequate climate control.

A surface plate should be supported at 3 points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered. Only 3 points can rest solidly on anything but a precision surface.

The plate should be supported at these points during production, and it should be supported only at these three points while in use. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same 3 points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. All zhhimg steel stands have support beams designed to line up with the proper support points.

If the plate is properly supported, precise leveling is only necessary if your application calls for it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

Why Choose Granite for Machine Bases and Metrology Components?

The answer is 'yes' for almost every application. The advantages of granite include: No rust or corrosion, almost immune to warping, no compensating hump when nicked, longer wear life, smoother action, greater precision, virtually non-magnetic, low co-efficient of thermal expansion, and low maintenance cost.

Granite is a type of igneous rock quarried for its extreme strength, density, durability, and resistance to corrosion. But granite is also very versatile– it’s not just for squares and rectangles! In fact, Starrett Tru-Stone confidently works with granite components engineered in shapes, angles, and curves of all variations on a regular basis—with excellent outcomes.

Through our state of the art processing, cut surfaces can be exceptionally flat. These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components. Granite is:

machineable
precisely flat when cut and finished
rust resistant
durable
long lasting
Granite components are also easy to clean. When creating custom designs, be sure to choose granite for its superior benefits.

STANDARDS / HIGH WEAR APPLICATIONS
The granite utilized by ZhongHui for our standard surface plate products has high quartz content, which provides greater resistance to wear and damage. Our Superior Black and Crystal Pink colors have low water absorption rates, minimizing the possibility of your precision gages rusting while setting on the plates. The colors of granite offered by ZhongHui result in less glare, which means less eyestrain for individuals using the plates. We have chosen our granite types while considering thermal expansion in an effort to keep this aspect minimal.

CUSTOM APPLICATIONS
When your application calls for a plate with custom shapes, threaded inserts, slots or other machining, you’ll want to select a material like Black Diabase. This natural material offers superior stiffness, excellent vibration dampening, and improved machinability.

Yes, if they are not too badly worn. Our factory setting and equipment allow the optimum conditions for proper plate calibration and rework if necessary. Generally, if a plate is within .001" of the required tolerance, it can be resurfaced on-site. If a plate is worn to the point where it is more than .001" out of tolerance, or if it is badly pitted or nicked, then it will need to be sent to the factory for grinding prior to relapping.

Great care should be exercised in selecting an on-site calibration and resurfacing technician. We urge you to use caution in selecting your calibration service. Ask for accreditation and verify the equipment that the technician will use has a National Inspection Institution traceable calibration. It takes many years to learn how to properly lap precision granite.

ZhongHui provides quick turn-around on calibrations performed in our factory. Send your plates in for calibration if possible. Your quality and reputation depend on the accuracy of your measurement instruments including surface plates!

Our black surface plates have a significantly higher density and are up to three times as stiff. Therefore, a plate made of the black does not need to be as thick as a granite plate of the same size to have equal or greater resistance to deflection. Reduced thickness means less weight and lower shipping costs.

Beware of others who use lower quality black granite in the same thickness. As stated above, properties of granite, like wood or metal, vary by material and color, and is not an accurate predictor of stiffness, hardness, or wear resistance. In fact, many types of black granite and diabase are very soft and not suitable for surface plate applications.

No. The specialized equipment and training necessary to rework these items requires that they be returned to the factory for calibration and rework.

Yes. Ceramic and granite have similar characteristics, and the methods used to calibrate and lap granite can be used with ceramic items as well. Ceramics are more difficult to lap than granite resulting in a higher cost.

Yes, provided that the inserts are recessed below the surface. If steel inserts are flush with, or above the surface plane, they must be spot-faced down before the plate can be lapped. If required, we can provide that service.

Yes. Steel inserts with the desired thread (English or metric) can be epoxy bonded into the plate at the desired locations. ZhongHui uses CNC machines to provide the tightest insert locations within +/- 0.005”. For less critical inserts, our locational tolerance for threaded inserts is ±.060". Other options include steel T-Bars and dovetail slots machined directly into the granite.

Inserts that are properly bonded using high strength epoxy and good workmanship will withstand a great deal of torsional and shear force. In a recent test, using 3/8"-16 threaded inserts, an independent testing laboratory measured the force required to pull an epoxy-bonded insert from a surface plate. Ten plates were tested. Out of these ten, in nine cases, the granite fractured first. The average load at the point of failure was 10,020 lbs. for gray granite and 12,310 lbs. for black. In the single case where an insert pulled free of the plate, the load at the point of failure was 12,990 lbs.! If a work piece forms a bridge across the insert and extreme torque is applied, it is possible to generate enough force to fracture the granite. Partially for this reason, ZhongHui gives guidelines for the maximum safe torque that can be applied the epoxy bonded inserts: https://www.zhhimg.com/standard-thread-inserts-product/

Yes, but only at our factory. At our plant, we can restore almost any plate to 'like-new' condition, usually for less than half the cost of replacing it. Damaged edges can be cosmetically patched, deep grooves, nicks, and pits can be ground out, and the attached supports can be replaced. In addition, we can modify your plate to increase its versatility by adding solid or threaded steel inserts and cutting slots or clamping lips, per your specifications.

Why Choose Granite?
Granite is a type of igneous rock formed in the Earth millions of years ago. The composition of igneous rock contained many minerals such as quartz that is extremely hard and wear-resistant. In addition to hardness and wear resistance granite has approximately half the coefficient of expansion as cast iron. As its volumetric weight is approximately one third that of cast iron, granite is easier to manoeuvre.

For machine bases and metrology components, black granite is the colour most used. Black granite has a higher percentage of quartz than other colours and is, therefore, the hardest wearing.

Granite is cost-effective, and cut surfaces can be exceptionally flat. Not only can it be hand lapped to achieve extremes of accuracy, but re-conditioning can be performed without moving the plate or table off-site. It is entirely a hand lapping operation and generally costs much less than re-conditioning a cast iron alternative.

These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components such as the granite surface plate.

ZhongHui produces bespoke granite products that are created to support specific measurement requirements. These bespoke items vary from straight edges to tri squares. Due to the versatile nature of granite, the components can be produced to any size required; they are hard wearing and long-lasting.

Advantages of Granite Surface Plates
The importance of measuring on an even surface was established by British inventor Henry Maudsley in the 1800s. As a machine tool innovator, he determined that consistent production of parts required a solid surface for reliable measurements.

The industrial revolution created a demand for measuring surfaces, so engineering company Crown Windley created manufacturing standards. The standards for surface plates were first set by Crown in 1904 using metal. As the demand and cost for metal increased, alternative materials for the measuring surface were investigated.

In America, monument creator Wallace Herman established that black granite was an excellent surface plate material alternative to metal. As granite is non-magnetic and doesn’t rust, it soon became the preferred measuring surface.

A granite surface plate is an essential investment for laboratories and test facilities. A granite surface plate of 600 x 600 mm can be mounted on a support stand. The stands provide a working height of 34” (0.86m) with five adjustable points for levelling.

For reliable and consistent measurement results, a granite surface plate is crucial. As the surface is a smooth and stable plane, it enables instruments to be carefully manipulated.

The main advantages of granite surface plates are:

• Non-reflective
• Resistant to chemicals and corrosion
• Low coefficient of expansion compared with cart iron so less affected by temperature change
• Naturally rigid and hard-wearing
• The plane of the surface is unaffected if scratched
• Will not rust
• Non-magnetic
• Easy to clean and maintain
• Calibration and resurfacing can be done onsite
• Suitable for drilling for threaded support inserts
• High vibration damping

For many shops, inspection rooms and laboratories, precision granite surface plates are relied on as the basis for accurate measurement. Because every linear measurement depends on an accurate reference surface from which final dimensions are taken, surface plates provide the best reference plane for work inspection and layout prior to machining. They also are ideal bases for making height measurements and gaging surfaces. Further, a high degree of flatness, stability, overall quality and workmanship make them a good choice for mounting sophisticated mechanical, electronic and optical gaging systems. For any of these measurement processes, it is imperative to keep surface plates calibrated.

Repeat Measurements and Flatness
Both flatness and repeat measurements are critical to ensure a precision surface. Flatness can be considered as all points on the surface being contained within two parallel planes, the base plane and the roof plane. The measurement of distance between the planes is the overall flatness of the surface. This flatness measurement commonly carries a tolerance and may include a grade designation.

The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula:
Laboratory Grade AA = (40 + diagonal² / 25) x 0.000001 inch (unilateral)
Inspection Grade A = Laboratory Grade AA x 2
Tool Room Grade B = Laboratory Grade AA x 4

In addition to flatness, repeatability must be ensured. A repeat measurement is a measurement of local flatness areas. It is a measurement taken anywhere on the surface of a plate that will repeat within the stated tolerance. Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.

To ensure a surface plate meets both the flatness and repeat measurement specifications, manufacturers of granite surface plates should use Federal Specification GGG-P-463c as a basis for their specifications. This standard addresses repeat measurement accuracy, material properties of surface plate granites, surface finish, support point location, stiffness, acceptable methods of inspection and installation of threaded inserts.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

Checking Plate Accuracy
By following a few simple guidelines, an investment in a granite surface plate should last for many years. Depending on plate usage, shop environment and required accuracy, frequency of checking the surface plate accuracy varies. A general rule of thumb is for a new plate to receive a full recalibration within one year of purchase. If the plate is used frequently, it is advisable to shorten this interval to six months.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

An effective inspection program should include regular checks with an autocollimator, providing actual calibration of overall flatness traceable to National Institute of Standards and Technology (NIST). Comprehensive calibration by the manufacturer or an independent company is necessary from time to time.

Variations Between Calibrations
In some cases, there are variations between surface plate calibrations. Sometimes factors such as surface change resulting from wear, incorrect use of inspection equipment or use of noncalibrated equipment can account for these variations. The two most common factors, however, are temperature and support.

One of the most important variables is temperature. For instance, the surface might have been washed with a hot or cold solution prior to calibration and not allowed sufficient time to normalize. Other causes of temperature change include drafts of cold or hot air, direct sunlight, overhead lighting or other sources of radiant heat on the surface of the plate.

There also can be variations in the vertical temperature gradient between winter and summer. In some cases, the plate is not allowed sufficient time to normalize after shipment. It is a good idea to record the vertical gradient temperature at the time the calibration is performed.

Another common cause for calibration variation is a plate that is improperly supported. A surface plate should be supported at three points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered.

Only three points can rest solidly on anything but a precision surface. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same three points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. Consider using steel stands with support beams designed to line up with the proper support points. Stands for this purpose are generally available from the surface plate manufacturer.

If the plate is properly supported, precise leveling is only necessary if an application specifies it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

It is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in workpieces and the contact surfaces of gages. Cover plates to protect them from dust and damage. Wear life can be extended by covering the plate when not in use.

Extend Plate Life
Following a few guidelines will reduce wear on a granite surface plate and ultimately, extend its life.

First, it is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in workpieces and the contact surfaces of gages.

It also is important to cover plates to protect it from dust and damage. Wear life can be extended by covering the plate when not in use.

Rotate the plate periodically so that a single area does not receive excessive use. Also, it is recommended to replace steel contact pads on gaging with carbide pads.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

Where to Relap
When a granite surface plate needs re-surfacing, consider whether to have this service performed on-site or at the calibration facility. It is always preferable to have the plate relapped at the factory or a dedicated facility. If, however, the plate is not too badly worn, generally within 0.001 inch of the required tolerance, it can be resurfaced on-site. If a plate is worn to the point where it is more than 0.001 inch out of tolerance, or if it is badly pitted or nicked, then it should be sent to the factory for grinding prior to relapping.

A calibration facility has the equipment and factory setting providing the optimum conditions for proper plate calibration and rework if necessary.

Great care should be exercised in selecting an on-site calibration and resurfacing technician. Ask for accreditation and verify the equipment that the technician will use has a NIST-traceable calibration. Experience also is an important factor, as it takes many years to learn how to correctly lap precision granite.

Critical measurements start with a precision granite surface plate as a baseline. By ensuring a reliable reference by using a properly calibrated surface plate, manufacturers have one of the essential tools for reliable measurements and better quality parts.

Checklist for Calibration Variations

1. The surface was washed with a hot or cold solution prior to calibration and was not allowed sufficient time to normalize.
2. The plate is improperly supported.
3. Temperature change.
4. Drafts.
5. Direct sunlight or other radiant heat on the surface of the plate. Be sure that overhead lighting is not heating the surface.
6. Variations in the vertical temperature gradient between winter and summer. If at all possible, know the vertical gradient temperature at the time the calibration is performed.
7. Plate not allowed sufficient time to normalize after shipment.
8. Improper use of inspection equipment or use of noncalibrated equipment.
9. Surface change resulting from wear.

Tech Tips
Because every linear measurement depends on an accurate reference surface from which final dimensions are taken, surface plates provide the best reference plane for work inspection and layout prior to machining.

Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.