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Linch Machinery Co. Ltd. Quality Control

Hey Sarah, Fittings and valves are perfect! Im going to make a list of fittings to order with in the next month for stock in my shop. Thanks again.

—— James Procyk

Hi Sarah, Everything arrived in good condition and quality is high and very acceptable. I am very happy with the service you provided, well done !

—— Thomas Thistlethwayte

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Production and Quality Control


1. The raw material we use:


                                       Sealing Material               Stainless Steel Stick (304 / 316L)


               Forged Parts                                 Casting Parts                       Stainless Steel Tube


2. How we control material quality?


The following tests are 100% conducted on-site:


    Visually check appearance and surface quality          PMI test to verify metal element ratio


3. Forming Machine Process


        CNC Lathe Processing              Milling Machine Processing             Punching Press Drilling            


        Punching Press Drilling                Cold Forming Molding                       Welding Assembly


4. How do we control the quality of machining


          CNG Lathes from                   Advanced Milling Machines                      UT Inspection  

         YAMAZAKI MAZAK                                                                          to ensure welding quality


              Weld Polishing            100% Appearance & Size Inspection    Size & Appearance Shaping

                                                  online (thickness, roundness, etc.)


5. Surface Treatment


We offer the following processes to choose:

                        Mechanical Polishing (MP)                       Acid Cleaning for Anti-corrosion

                 to improve brightness (gloss, matte)


                           Electrolysis Polish (EP)                 Custom Process: Bright Annealing treatment

                  to improve surface smoothness                   eliminate strees to improve toughness


6. How do we ensure surface quality


                                 Visual Inspection                                     Roughness Detection


7. Assembly and marking


                                    Assembly                                                         Marking


8. How do we ensure finished product quality (FQC inspection)


             Visual Inspection                Material Grade Measurement             Dimension Inspection


         Roughness Detection                  Roughness Detection                          Leakage Test


9. Cleaning and packing


       Ultrasonic Cleaning Sink                           Packing                                        Packing

Contact Details
Linch Machinery Co. Ltd.

Contact Person: Miss. Sarah Ding

Tel: 86-510-66066856

Fax: 86-510-66066856

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