Priority is given to Jinan Green and Zhangqiu Black dense fine-grained granite, meeting the following mandatory specifications:
Density \u2265 2.6g\/cm\u00b3, Mohs hardness 6~7, compressive strength \u2265 80MPa
Water absorption \u2264 1.0%, coefficient of thermal expansion 4.5~6\u00d710\u207b\u2076\/\u2103, non-magnetic, high damping vibration reduction
Prohibited raw materials: those with bedding, large mica patches, dark cracks, pores, or color bands.<\/li>\n\n\n\n
Natural aging outdoors for over 3 months to release the original rock layer stress from the mine;
Ultrasonic internal flaw detection to screen for invisible dark cracks;
Tap testing to screen for internal loose defects;
Full appearance inspection: reject cracks, color spots, and cavities; high-precision bases must be monolithic without joints.
II. Rough Cutting and Blank Shaping (Reserving Machining Allowance for Precision Processing)
Diamond large saw cutting of rough blocks
Frame saw \/ wire saw water-cooled cutting with continuous spraying for cooling to avoid thermal stress cracking; reserve 2mm for length and width, and 2~3mm for thickness as machining allowance.
CNC Shaping and Rough Machining
Bridge cutting machine and water jet cutting for external contours, milling off excess corners; rough grinding of reference surfaces, with flatness controlled at 0.2mm\/m after rough grinding.
Rough Milling of Functional Blanks
Pre-drilling of mounting holes and rough milling of T-slots, leaving 0.5~1mm of precision grinding allowance on each side; strictly prohibit deep single-pass cutting to prevent edge chipping and micro-cracks.
III. Multi-stage Stress Release Aging (Determines Long-term Dimensional Stability, Core Process)
Internal cutting stress exists in the stone after rough machining; if not released, direct precision grinding will lead to long-term slow deformation and precision drift.
Option 1: Natural Constant Temperature Aging (Standard for High-end Grade 000 Platforms)
Move components to a constant temperature and humidity workshop (20\u00b11\u2103, humidity 45\u00b15% RH), place them flat and let them rest for 2~4 weeks, flipping them every 7 days to release stress uniformly.
Option 2: Artificial Composite Aging (For Mass-produced Precision Parts)
Thermal aging: 24h insulation in an 80\u2103 drying room;
Cryogenic cycling: 4h insulation at -10\u2103;
Return to 20\u2103 constant temperature and rest for 72h;
Thoroughly eliminate residual stresses generated by cutting and sawing.
IV. Multi-stage Precision Grinding (Achieving Micron \/ Sub-micron Reference Precision)
The entire process is completed in a 20\u2103 constant temperature workshop, divided into 4 gradient grinding stages to progressively improve flatness and surface finish:
Semi-precision Grinding (200#~400# diamond grinding wheels)
Remove rough machining tool marks, flatness controlled at 0.02~0.05mm\/m;
Fine Grinding (800#~1200#)
Eliminate deep and shallow scratches, surface roughness Ra < 0.8\u03bcm;
Ultra-precision Manual Lapping (2000#~5000# ultra-fine abrasives)
Technicians use cast iron lapping plates for cross-pattern grinding, gradually converging the flatness error;
Mirror Polishing (Above 5000#)
Working surface Ra \u2264 0.1~0.2\u03bcm, sealing pores to prevent water and oil penetration.
After grinding, let it rest again in a constant temperature environment for 5~7 days for secondary stress release to prevent precision rebound.<\/li>\n<\/ol>\n\n\n\n
V. Precision Machining of Functional Components (Assembly and Supporting Structures) Granite Precision Instrument Components: Raw Material \u2192 Finished Product Processing Full-Process Calibration TechnologyApplicable Products: CMM bases, semiconductor metrology platforms, machine tool beds, optical inspection reference tables (Grade 00 \/ Grade 000 high-precision granite components)The overall process is divided into seven complete stages: Raw Material Selection \u2192 Rough Machining and Shaping \u2192 Stress Aging and Stabilization…<\/p>","protected":false},"author":1,"featured_media":2587,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_kadence_starter_templates_imported_post":false,"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","footnotes":""},"categories":[35],"tags":[],"class_list":["post-3043","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"taxonomy_info":{"category":[{"value":35,"label":"NEWS"}]},"featured_image_src_large":["https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/04\/\u5fae\u4fe1\u56fe\u7247_20260428145938_16_25.png",799,784,false],"author_info":{"display_name":"jinxing6611@gmail.com","author_link":"https:\/\/jtlcnc.com\/ar\/author\/jtlcnc\/"},"comment_info":0,"category_info":[{"term_id":35,"name":"NEWS","slug":"news","term_group":0,"term_taxonomy_id":35,"taxonomy":"category","description":"","parent":0,"count":310,"filter":"raw","cat_ID":35,"category_count":310,"category_description":"","cat_name":"NEWS","category_nicename":"news","category_parent":0}],"tag_info":false,"_links":{"self":[{"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/posts\/3043","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/comments?post=3043"}],"version-history":[{"count":1,"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/posts\/3043\/revisions"}],"predecessor-version":[{"id":3044,"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/posts\/3043\/revisions\/3044"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/media\/2587"}],"wp:attachment":[{"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/media?parent=3043"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/categories?post=3043"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/tags?post=3043"}],"curies":[{"name":"\u062f\u0628\u0644\u064a\u0648 \u0628\u064a","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Precision drilling, tapping, and pre-embedding of stainless steel threaded sleeves (to prevent stripping and corrosion);
CNC machining and grinding of T-slot and V-guide surfaces to ensure straightness and perpendicularity;
Precision machining of weight-reduction cutouts, lifting slots, and positioning datum bosses;
Surface sealing and protection: Specialized stone penetrative sealant to reduce water absorption and prevent moisture erosion.
VI. Full Factory Calibration and Inspection (Metrological-grade calibration, issuance of calibration certificates)
Pre-calibration Environmental Requirements
Constant temperature of 20\u00b11\u00b0C, temperature change rate \u22640.5\u00b0C\/h, vibration-free, dust-free, and components must be kept at a constant temperature for 24 hours for equilibrium.
Full Calibration Items and Equipment (In accordance with JJG 117 and ISO 8512 standards)
Appearance and Defect Inspection
Visual inspection magnifying glass to check for scratches, dents, and cracks;
Flatness Calibration (Core Indicator)
Grade 000\/00 Ultra-high Precision: Laser interferometer, autocollimator, and grid point measurement;
Conventional Precision Parts: Electronic level bridge plate five-point grid method;
Grid collection of hundreds of points based on dimensions, least squares plane fitting, error control:
Grade 000: \u22641.5\u03bcm\/m; Grade 00: \u22643\u03bcm\/m; Grade 0: \u22646\u03bcm\/m
Parallelism Calibration
Dial indicator standard straightedge multi-point scanning to detect parallelism deviation of upper and lower working surfaces;
Perpendicularity \/ Straightness Calibration
Autocollimator to detect side straightness, guide rail datum straightness, and datum surface perpendicularity;
Dimension and Thickness Uniformity
High-precision grating calipers and Coordinate Measuring Machine (CMM) to verify length, width, and thickness tolerances;
Roughness Inspection
Surface roughness tester to measure working surface Ra;
Stability Re-testing
After calibration, the component is kept at a constant temperature for 48 hours for re-testing of flatness; it is only qualified if there is no precision rebound.
Output Documents
Granite platform factory calibration report, precision grade marking, and factory quality certificate.
VII. Factory Protection, Transportation, and On-site Secondary Calibration for Equipment Installation
Packaging Protection
Working surfaces wrapped in soft foam, secured in solid wood frames for shock absorption to avoid micro-deformation caused by transportation bumps;
On-site Re-testing and Calibration After Equipment Installation
After the granite base is transported to the instrument workshop, it must not be leveled immediately. A three-step on-site calibration must be performed:
1) Constant temperature rest for 24~48 hours to fully synchronize with the workshop environment temperature;
2) Rough leveling using adjustable support feet, followed by fine leveling with an electronic level;
3) Laser interferometer to re-test datum flatness and guide rail straightness;
4) Linkage calibration with the instrument’s optical\/measurement system to compensate for minor installation deviations;
Periodic Calibration Specifications
Semiconductor \/ Optical Ultra-precision Equipment: On-site calibration every 6 months;
Ordinary Inspection Machine Tools: Annual calibration; if flatness exceeds tolerance, it must be returned to the factory for regrinding and repair.
VIII. Key Shortcomings of Granite Components Compared to SiC Ceramic Bases (Corresponding to your previous SiC comparison table)
Thermal conductivity of only 3~5W\/(m\u00b7K), making it impossible to embed water-cooling channels, and local heating easily causes warping;
Thermal expansion coefficient of 4.5~6\u00d710\u207b\u2076\/\u00b0C, with temperature-induced dimensional drift far higher than SiC;
Extremely heavy self-weight and poor lightweighting, making it unsuitable for aerospace and high-speed scanning lithography machines;
Surface wear from long-term reciprocating friction leads to a yearly decline in precision, making it only suitable for micron-level ordinary equipment and unable to meet the nanometer-level thermal control requirements of advanced semiconductors.<\/p>\n\n\n\n![\"\"](\"https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/06\/20260603-151535.png\")
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