Valve grinding is a light finishing method with a very small cutting volume, and generally, there are few grinding rejects. Valve sealing surface because the dimensional accuracy is not very high, grinding scrap is rarer. Sealing surface grinding often occurs in the geometry is incorrect, surface scratches and pulling grooves and other defects. Common defect forms, causes, and prevention methods are shown below.

Defect form: Scratch

Cause 1: Abrasive mixed with individual coarse abrasive particles

Prevent method 1: Use the water sedimentation method to sort the abrasives and strengthen the storage of abrasives.

Cause 2: Dust, iron chips, or other debris are mixed in the abrasive

Prevent method 2: The container of abrasive should be covered, and the configuration should be kept clean.

Cause 3: The workpiece is not clean or has burrs

Prevent method 3: The sealing surface should be deburred and cleaned before grinding

Cause 4: The lapping machine or grinding tool is not clean

Prevent method 4: the best primary research machine and fine research are very separate, and pay attention to the lapping machine and research tool cleaning

Cause 5: Too much dust in the workshop

Prevention method 5: Establish a closed grinding room and keep it clean.

Defective form: incorrect geometry

Cause 1: Improper grinding motion

Prevention method 1: Improve the grinding motion

Cause 2: Abrasive is too thick or unevenly applied

Prevention method 2: Use thinner abrasive and pay attention to uniform application

Cause 3: Uneven grinding pressure

Prevent method 3: Even and consistent force when grinding by hand

Cause 4: Poor processing accuracy in the previous process

Prevention method 4: Improve the processing accuracy of the previous process and pay attention to prevent the deformation of the workpiece

Cause 5: Grinding time is too long

Prevention method 5: Reduce the grinding allowance, try coarser abrasives or improve the grinding speed and increase the grinding pressure

Cause 6: inaccurate grinding tools

Prevention method 6: frequent inspection and repair of the grinding tool, the grinding tool wears out too fast can be replaced with other wear-resistant materials

Defect form: knife marks

Cause 1: The quality of the previous process is not good, the luminosity is too low

Prevention method 1: The workpiece should be ground before grinding, and the luminosity should not be lower than 6 when using fine turning.

Cause 2: Abrasive is too coarse

Prevent method 2: use fine abrasives

Cause 3: The cutting heat generated during grinding is too high

Prevention method 3: reduce the grinding pressure, reduce the grinding speed and often add abrasive

Know about Metals Kingdom Industry Limited

Metals Kingdom Industry Limited is a professional manufacturer of Testing and Repair Equipment for Valves & Pipes since 1994. Our Portable Valve Grinding Machine, Valve Test Bench Connecting rod synchronous telescopic mechanism, Portable Pipe Beveling Machine, Pipe Beveling and Cutting Machine all gained the National Patent for utility models in 1996 and 2014, our factory passed ISO Quality Management Certificate in 2008, and got the Certificate of Material Supplier by China National Petroleum Corporation and National Power Corp.