When the mass production of plastic injection molded products is being carried out, there will always be some wearing out or breakage of parts of the mold for plastic injection molding. In such situations, it is necessary to carry out maintenance by replacing parts or making repairs. The common items that require maintenance are the following.

	-	Depressions, scratches and wear of the parting surface
	-	Chipping or depressions on the corners of the cavity
	-	Wear and scraping of the locking block
	-	Wear and cracks of the anguled pin
	-	Wear and scraping of the guide post
	-	Wear and scraping of the guide bush
	-	Scraping of the rail guide by the slide core
	-	Scraping of the center rail
	-	Wear and deformation of the gate
	-	Wear of the internal surface of the sprue bush
	-	Depressions and deformation of the nozzle touching part of the sprue bush
	-	Weakening of the spring elasticity
	-	Wear of the ejector pin
	-	Wear of the hole of the ejector pin
	-	Wear and scraping of the positioning block
	-	Wear and scraping of the return pin
	-	Scraping of the stripper plate
	-	Scraping of the runner stripper plate
	-	Elongation of the bolt
	-	Wear to the bolt threads
	-	Wear of the coupler for the cooling water
	-	Punctures and open circuits in the cartridge heater
	-	Rust and clogging inside the hole for the cooling water
	-	Rust and mold in the periphery of the mold base
	-	Open circuits in the electrical wires and cracks in the cable covering
	-	Fault in the contacts of the limit switches
	-	Clogging due to soot in the air vents
	-	Deformation due to temporal changes in the frame block