Injection mold is a tool for producing plastic products; it is also a tool that gives plastic products complete structure and dimensions. The structural form and processing quality of the injection mold directly affect the quality of the plastic parts and production efficiency. Injection mold assembly is an important post-process in the injection mold manufacturing process. Mold quality is closely linked to mold assembly. Mold parts are processed through milling, drilling, grinding, CNC, EDM, turning, and other processes. After passing inspection, they are concentrated in the assembly process. The quality of assembly directly affects the quality of the mold and is one of the determining factors of mold quality. Without high-quality mold parts, there would be no high-quality mold; only with high-quality mold parts and high-quality mold assembly technology can there be a high-quality injection mold.

Today, we will introduce the assembly process of injection molds based on professional plastic mold manufacturing courses and 3D interactive resources.
Assembling the Fixed Half Components:
Select the assembly datum part. According to the assembly drawing, the cavity plate is selected as the assembly datum for the fixed half component.
Assembling Guide Bushings: Insert the guide bushings into the holes of the cavity plate. During installation, it must be ensured that the center of the guide bushing is perpendicular to the parting line of the cavity plate.
Assembling Small Cores: Insert the small cores into the corresponding holes in the cavity plate and ensure accurate surface fit.
After assembly, place the cavity plate on a surface grinder. Using the parting line of the cavity plate as a datum, grind the top surface of the cavity plate, the top end of the guide bushings, and the top end of the small cores to be flush.

Assembling the Fixed Seat Plate:
Assemble the fixed seat plate onto the top surface of the cavity plate, ensuring the mating surfaces of the two plates fit tightly without any wobbling.
Assembling the Sprue Bushing: Adjust the fit position of the sprue bushing hole in the center of the cavity plate, fit the sprue bushing into it, and ensure that the bottom surface of the sprue bushing is flush with the parting line of the cavity plate.
Assembling Fixed Seat Plate Fastening Screws: Align the screw holes between the fixed seat plate and the cavity plate, screw in the bolts, and tighten them in a symmetrical pattern.
Assembling the Locating Ring: Ensure the inner hole of the locating ring fits with the outer ring of the sprue bushing, while the outer ring of the locating ring fits with the corresponding hole in the fixed seat plate.
Assembling Locating Ring Fastening Screws: Align the screw holes between the locating ring and the fixed seat plate, screw in the bolts, and tighten them in a symmetrical pattern.
Assembling Pipe Fittings: Install the pipe fittings into the cooling water holes on both sides of the cavity plate, ensuring proper sealing at the installation points.

Assembling the Movable Half Components:
Select the assembly datum part. According to the assembly drawing, the core retainer plate is selected as the assembly datum for the movable half component.
Assembling Guide Pillars: Propped up the core retainer plate using equal-height parallel blocks, and use a press machine to press the guide pillars into the holes. Ensure the center of the guide pillar is perpendicular to the surface of the plate during pressing.
Assembling Large Cores: Insert the large cores into the corresponding holes in the core retainer plate and ensure accurate surface fit.
After assembly, check if the mating surfaces of the core retainer plate are flush. If not, use a surface grinder for rectification.
Assembling Core Backing Plate:
Align the core backing plate with the core retainer plate. During assembly, check if the two plates fit tightly without wobbling.
Assembling Return Pin Components: Insert the return pins into the ejector plate; the bottom surface of the return pins must not be higher than the bottom surface of the ejector plate.
Insert the sprue puller pin into the ejector plate; the bottom surface of the puller pin must not be higher than the bottom surface of the ejector plate.
Assembling Ejector Backing Plate: Use assembly screws to fix the return pin components into the core backing plate.

Assembling Backing Plate:
Note the installation position and direction.
Assembling Movable Seat Plate:
Note the installation position and direction.
Assembling Screws: Install the fastening screws for the movable seat plate and tighten them symmetrically.
Assembling Stop Pins: Install stop pins according to the positions and requirements on the assembly drawing.
Mold Closing (Mold Fitting): Trim the return pins, check if the top surface of the return pins is flush with the top surface of the core retainer plate. If the return pin is higher, use a diamond file or grinding wheel for trimming.
Assembling Core Plate Components: Install the slide bushings into the holes of the core plate, ensuring they meet fit requirements. Using the center of the slide bushing as a datum, assemble the core plate component onto the guide pillars for mold closing.
Before closing the mold, confirm once more that all screws are tightened.
During mold closing, align the guide pillars with the guide bushings, slide the fixed half component in parallel, and use a feeler gauge to check the contact of the parting line between the fixed and movable halves. Generally, the contact gap should not exceed 0.4mm.

The above covers part of the injection mold assembly process.