Basic procedures for polishing plastic molds
To achieve high-quality polishing results, the most important thing is to have high-quality polishing tools and accessories such as oilstones, sandpaper, and diamond grinding paste. The general process of polishing plastic molds is as follows:

1. Fine polishing
Fine polishing mainly uses diamond grinding paste. If diamond grinding powder or paste is mixed with a polishing cloth wheel for grinding, the usual grinding sequence is 9um (# 1800)~6um (# 3000)~3um (# 8000). A 9um diamond grinding paste and polishing cloth wheel can be used to remove hair like grinding marks left by # 120O and # 1500 sandpaper. Next, polish with adhesive felt and diamond grinding paste in the order of 1um (# 14000)~1/2um (# 60000)~1/4um (# 100000). Polishing processes with an accuracy requirement of 1um or above (including 1um) can be carried out in a clean polishing room in the mold processing workshop. If more precise polishing is performed, an absolutely clean space is necessary. Dust, smoke, dandruff, and saliva can all potentially scrap high-precision polished surfaces obtained after working for several hours.

2. Rough throwing
After milling, electrical discharge, grinding and other processes, the surface can be polished using a rotary surface polishing machine or ultrasonic grinding machine with a speed of 35000-400 O00 rpm. The commonly used method is to use a wheel with a diameter of 3mm and WA # 400 to remove the white spark layer. Then there is manual oilstone grinding, with strip shaped oilstones mixed with kerosene as a lubricant or coolant. The general usage order is # 180~# 240~# 320~# 40O~# 600~# 800~# 1000. Many mold manufacturers choose to start from # 400 in order to save time.

3. Semi precision polishing
Semi precision polishing mainly uses sandpaper and kerosene. The numbers of sandpaper are: # 40O~# 600~# 800~# 1000~# 1200~# 1500. In fact, # 1500 sandpaper is only suitable for hardened mold steel (above 52HRC), and not for pre hardened steel, as this may cause surface burns on pre hardened steel parts.

4. Fine polishing
By using grinding paste for precision polishing, 8000010000 can achieve a mirror finish. Precautions for plastic mold assembly
Different types of plastic molds and different types of formed plastics (the same type of mold) have different assembly methods due to different beginning and precision requirements. So, before assembly, it is necessary to carefully study and analyze the final assembly drawing and parts drawing. By understanding the functions, characteristics, and technical requirements of each component, determine the assembly benchmark. After careful assembly, various quality indicators of the product have been achieved, including mold action accuracy and other technical requirements during use.
Precautions for plastic mold assembly

Different types of plastic molds and different types of formed plastics (the same type of mold) have different assembly methods due to different beginning and precision requirements. So, before assembly, it is necessary to carefully study and analyze the final assembly drawing and parts drawing. By understanding the functions, characteristics, and technical requirements of each component, determine the assembly benchmark. After careful assembly, various quality indicators of the product have been achieved, including mold action accuracy and other technical requirements during use.
1. Assembly reference
Assembly reference refers to the reference used to determine the relative position of parts or components in the product during assembly, which can be roughly divided into: (1) using main working parts such as cores, cavities, and inserts as assembly reference parts;
(2) Use the template side base surface of the guide pillar guide sleeve or mold as the assembly reference surface.

2. Assembly accuracy

Assembly accuracy refers to the geometric accuracy, machining accuracy, motion accuracy, etc. of the equipment after assembly. The assembly accuracy of plastic molds includes: (1) the mutual accuracy of various components, such as distance dimension accuracy, coaxiality, equality, verticality, etc;
(2) Relative motion accuracy, such as transmission accuracy, linear motion accuracy, and rotational motion accuracy;
(3) Fit accuracy and contact accuracy, such as fit clearance, interference and contact condition;
(4) The wall thickness of plastic formed parts should deviate from the lower limit of the size when making new molds.

3. Repair principle:

(1) Repair the demolding slope. In principle, the cavity should ensure that the large end size is within the tolerance range of the workpiece size, and the core should ensure that the small end size is within the tolerance range of the workpiece size; (2) The radius of the rounded corners should be smaller for the cavity and larger for the core;
(3) When the mold has both horizontal and vertical parting surfaces, the correction should leave a slight gap on the horizontal parting surface when the vertical parting surface contacts. Small molds only need to be painted red and in contact with each other, while large molds have a gap of about 0.02mm;
(4) For molds with inclined surfaces, there should be a gap of 0.02-0.03mm at the parting surface after the inclined surfaces are tightly sealed;
(5) The arc and straight line connection on the repair surface should be smooth, and there should be no dents on the surface. The filing pattern should be consistent with the direction of the mold opening.