{"id":3404,"date":"2026-09-14T10:27:16","date_gmt":"2026-09-14T02:27:16","guid":{"rendered":"https:\/\/jtlcnc.com\/?p=3404"},"modified":"2026-09-14T10:27:18","modified_gmt":"2026-09-14T02:27:18","slug":"key-production-technologies-of-large-precision-granite-worktables","status":"publish","type":"post","link":"https:\/\/jtlcnc.com\/fr\/2026\/09\/14\/key-production-technologies-of-large-precision-granite-worktables\/","title":{"rendered":"Key production technologies of large precision granite worktables"},"content":{"rendered":"

Key Production Technologies for Large Precision Granite Worktables (CMM \/ Metrology Bases)<\/p>\n\n\n\n

Core Logic: Raw Material Selection \u2192 Multi-stage Stress Relief Aging \u2192 Graded CNC Grinding \u2192 Constant Temperature Ultra-precision Polishing \u2192 Precision Hole \/ Insert Integration \u2192 Constant Temperature Closed-loop Inspection \u2192 Lifting and Support Design<\/strong>; The biggest challenge for 00\/000 grade large platforms is not simply grinding the surface, but controlling long-term stress creep, suppressing temperature difference deformation, and ensuring global surface flatness uniformity<\/strong>.<\/p>\n\n\n\n

I. Raw Material Selection and Billet Quality Control (Source Stability)<\/h6>\n\n\n\n

The first threshold determining long-term dimensional stability. Priority is given to Jinan Blue (Spodumene Granite)<\/strong>, characterized by fine grain, low expansion, and high density.<\/p>\n\n\n\n

    \n
  1. Material Indicators: Density \u2265 3.07g\/cm\u00b3, water absorption \u2264 0.1%, linear expansion coefficient \u2264 4.5\u00d710\u207b\u2076\/\u2103, Shore hardness \u2265 80HSD, uniform grain size 0.1~0.3mm, free of sand holes, color lines, inclusions, and micro-cracks.<\/li>\n\n\n\n
  2. Non-destructive Testing: Ultrasonic testing of the billet’s interior to detect micro-cracks and eliminate hidden cracks and stress concentration areas; blasting for billet extraction is strictly prohibited (blasting introduces deep residual stress); diamond wire saws are used for extraction and cutting.<\/li>\n\n\n\n
  3. Billet Aging: Ultra-large billets undergo open-air natural aging for 18~24 months<\/strong>, utilizing seasonal temperature variations to slowly release the rock mass’s original internal stress; unstable blanks will crack or delaminate during the aging stage and be eliminated early to prevent later creep deformation of the finished product.<\/li>\n<\/ol>\n\n\n\n
    II. Multi-stage Residual Stress Relief Aging Technology (Core Process)<\/h6>\n\n\n\n

    Granite rough cutting and milling introduce machining stresses. Insufficient stress relief causes the finished product to slowly warp and its flatness to drift after a few months of use. Aging is divided into three stages:<\/p>\n\n\n\n

      \n
    1. Blank Natural Aging<\/strong>: The billet is left to rest in the open air or a constant temperature warehouse after being sawn into a blank.<\/li>\n\n\n\n
    2. Secondary Aging After Rough Machining<\/strong>: Diamond grinding wheels are used to rough-mill the six sides, leaving a 0.81.5mm allowance for precision machining on each side, followed by constant temperature thermal aging<\/strong>: heating rate \u2264 58\u2103\/h, holding at 5560\u2103 (large pieces held for 72h); cooling rate 35\u2103\/h, rapid cooling is strictly prohibited to prevent cracks. Vibration aging can also be used to assist in releasing surface machining stresses.<\/li>\n\n\n\n
    3. Constant Temperature Resting Aging After Semi-precision Grinding<\/strong>: The piece is transferred to a 20\u2103 constant temperature workshop to rest for 2~4 weeks, with regular flipping to ensure uniform release of machining stresses; 000 grade products must rest in a constant temperature environment for over 72h after precision polishing, followed by flatness re-testing to eliminate precision rebound.<\/li>\n<\/ol>\n\n\n\n
      III. Rough Machining and Datum Forming Technology for Large Components<\/h6>\n\n\n\n
        \n
      1. Diamond wire saws bridge cutting machines for material removal, water-cooled cutting to reduce cutting thermal stress; a 3~5mm allowance is reserved on each side.<\/li>\n\n\n\n
      2. Gantry five-axis stone processing centers are used to rough-mill the external shape, datum surfaces, T-slots, and mounting holes; mutually constrained six-side datums are established to initially control parallelism and perpendicularity.<\/li>\n\n\n\n
      3. Steel Insert Embedding Technology: For threaded holes, locating holes, and air bearing mounting holes, stainless steel pre-embedded bushings are used with specialized low-shrinkage epoxy bonding. After curing and resting, secondary grinding is performed to prevent inserts from causing local stress and height differences; hole spacing and perpendicularity are corrected in a closed loop.<\/li>\n<\/ol>\n\n\n\n

        Note: Drilling, slotting, and insert embedding must be completed before precision polishing<\/strong>. Inserts will undergo minute deformation after curing, requiring subsequent grinding for unified correction.<\/p>\n\n\n\n

        IV. Graded Precision Grinding and Constant-Temperature Ultra-Precision Polishing (Determining Final Flatness)<\/h6>\n\n\n\n

        Environmental Prerequisites<\/p>\n\n\n\n

        Finishing, polishing, and inspection are uniformly conducted in a constant temperature and humidity, vibration-isolated, dust-free workshop<\/strong>: 20\u00b0C \u00b1 0.5\u00b0C, hourly temperature fluctuation < 0.3\u00b0C; humidity 45~55% RH; independent vibration-damping foundation, vibration acceleration < 0.01g; Class 10,000 cleanroom to prevent abrasive particles from scratching the working surface.<\/p>\n\n\n\n

          \n
        1. Multi-stage CNC Gantry Precision Grinding\n
            \n
          • Rough grinding \u2192 Semi-fine grinding \u2192 Fine grinding: progressively increase diamond grinding wheel grit (80# \u2192 240# \u2192 800#), gradually reduce cutting amount, use low pressure and low speed, ensure sufficient water cooling, and strictly control thermal deformation caused by local temperature rise;<\/li>\n\n\n\n
          • For large worktables, do not grind only the center; adopt a cross diagonal grid grinding path<\/strong> to control waviness across the entire surface and prevent edge collapse.<\/li>\n<\/ul>\n<\/li>\n\n\n\n
          • Ultra-precision Manual \/ CNC Composite Polishing (Core of Grade 00, 000)
            Three-stage polishing: Rough polishing \u2192 Fine polishing \u2192 Ultra-fine polishing; use cast iron polishing tools progressive polishing pastes (Alumina \u2192 Ceria), cross-diagonal reciprocating polishing, and point-by-point correction of high and low errors;\n
              \n
            • Grade 000 working surface Ra \u2264 0.01~0.02\u03bcm; flatness according to GB\/T20428 or DIN876, achieving micron \/ sub-micron level global flatness;<\/li>\n\n\n\n
            • Perform surface micropore sealing treatment after polishing to reduce hygroscopicity, preventing oil and water vapor from penetrating the stone interior and causing micro-expansion deformation.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n
              V. Closed-loop Geometric Accuracy Inspection Technology<\/h6>\n\n\n\n

              Large platforms cannot be measured at single points only; adopt a cross-grid point layout diagonal measurement<\/strong>:<\/p>\n\n\n\n

                \n
              1. Instruments: Laser interferometer, electronic autocollimator, high-precision level;<\/li>\n\n\n\n
              2. Rules: Workpieces must be pre-placed in a constant temperature environment for isothermal stabilization \u2265 2h; inspection is performed only after the workpiece and measuring tools reach the same temperature;<\/li>\n\n\n\n
              3. Inspection items: Flatness, diagonal difference, parallelism of top and bottom surfaces, perpendicularity of side surfaces, position accuracy of holes, and perpendicularity of hole axes to the working surface;<\/li>\n\n\n\n
              4. Stability verification: Re-measure after constant temperature stabilization for 3~7 days to confirm no stress rebound; the product can only be shipped after accuracy is stabilized.<\/li>\n<\/ol>\n\n\n\n
                VI. Mechanical Support, Lifting, and Structural Optimization Technology (Crucial but easily overlooked)<\/h6>\n\n\n\n

                Large granite has high rigidity but high brittleness; the support method directly affects the apparent flatness of the measuring surface<\/strong>:<\/p>\n\n\n\n

                  \n
                1. Three-point \/ Multi-point adjustable support design: Adopt the classic triangular statically determinate support<\/strong>; for large components, add auxiliary supports, use finite element simulation to calculate self-weight deflection, optimize support positions, and avoid self-weight bending; local stress buffering is applied to support points to prevent cracking.<\/li>\n\n\n\n
                2. Dedicated lifting structure: Pre-embed metal lifting bushings; direct binding of stone edges is prohibited; lifting plans undergo finite element stress verification to ensure no plastic micro-deformation occurs during lifting.<\/li>\n\n\n\n
                3. Cross-section and rib optimization: For ultra-large monolithic worktables, use thickening and back-side weight-reducing rib grooves to control self-weight deflection while reducing weight; after machining weight-reducing grooves, add a stress-releasing groove to relieve machining stress.<\/li>\n<\/ol>\n\n\n\n
                  VII. Defect Repair and Protection Technology<\/h6>\n\n\n\n
                    \n
                  1. Tiny sand holes, shallow pits: Remove the defective area, use low-shrinkage, low-expansion specialized mineral epoxy for repair, and re-polish after curing to ensure the deformation consistency between the repaired area and the substrate; cracks are generally judged as scrap and not simply filled on the surface.<\/li>\n\n\n\n
                  2. Finished product protection: Perform pore-sealing passivation treatment on the working surface to reduce water absorption; chamfer edges to prevent chipping; use flexible supports for packaging, ensure vibration reduction throughout transportation, and avoid rough loading and unloading.<\/li>\n<\/ol>\n\n\n\n
                      \n
                    1. Specialized process for air bearing base: integrated machining of guide rail datum surfaces, air hole arrays, and vacuum suction holes; multi-datum coupled grinding to ensure multi-surface form and position tolerance matching.<\/li>\n<\/ol>\n\n\n\n
                      Summary of Typical Process Chain<\/h5>\n\n\n\n

                      Raw material screening \u2192 Ultrasonic flaw detection \u2192 Long-term natural aging of raw material \u2192 Diamond wire sawing for blanking \u2192 Rough milling for shaping slotting, drilling, and bushing \u2192 Rough machining heat treatment \u2192 Semi-precision grinding \u2192 Constant temperature static aging \u2192 CNC precision grinding \u2192 Ultra-precision cross grinding \u2192 Hole sealing treatment \u2192 Constant temperature static stability testing \u2192 Full-parameter laser inspection \u2192 Support adjustment and factory inspection.<\/p>\n\n\n\n

                      \"\"<\/figure>","protected":false},"excerpt":{"rendered":"

                      Key Production Technologies for Large Precision Granite Worktables (CMM \/ Metrology Bases) Core Logic: Raw Material Selection \u2192 Multi-stage Stress Relief Aging \u2192 Graded CNC Grinding \u2192 Constant Temperature Ultra-precision Polishing \u2192 Precision Hole \/ Insert Integration \u2192 Constant Temperature Closed-loop Inspection \u2192 Lifting and Support Design; The biggest challenge for 00\/000 grade large platforms…<\/p>","protected":false},"author":1,"featured_media":3405,"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-3404","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\/09\/152-1024x723.png",1024,723,true],"author_info":{"display_name":"jinxing6611@gmail.com","author_link":"https:\/\/jtlcnc.com\/fr\/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":363,"filter":"raw","cat_ID":35,"category_count":363,"category_description":"","cat_name":"NEWS","category_nicename":"news","category_parent":0}],"tag_info":false,"_links":{"self":[{"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/posts\/3404","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/comments?post=3404"}],"version-history":[{"count":1,"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/posts\/3404\/revisions"}],"predecessor-version":[{"id":3406,"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/posts\/3404\/revisions\/3406"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/media\/3405"}],"wp:attachment":[{"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/media?parent=3404"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/categories?post=3404"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/tags?post=3404"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}