How to choose a good mould frame for mould?

The application of mold frame in engineering is more and more, how to choose the right one is a problem, today we summarize several guidelines of mold frame selection, take a look.

Mold frame generally uses standard mold frame and standard accessories, which helps to shorten the manufacturing cycle and reduce manufacturing costs. In actual production, often according to the price of the mold, structure, and the complexity of the mold frame processing to decide.

In special cases or when the customer specifies requirements, changes can be made to the shape, size, and material of the part of the mold frame, or the mold frame can be completely redesigned. In this case, when ordering the mold frame, it is necessary to provide the mold frame supplier with a detailed mold frame drawing and indicate the differences between the ordered mold frame and the standard mold frame.

Determine the size of the mold frame and inserts

The size of the mold mainly depends on the size and structure of the plastic product. For the mold surface, the more compact the structure is, the better, while ensuring sufficient strength. According to the size of the product (plane projection area and height) and the structure of the product itself (lateral parting slider and other structures), the size of the insert can be determined, and after determining the size of the insert, the size of the mold frame can be roughly determined.

Determine the height of the square iron

The height of the square iron should ensure enough ejecting stroke, and then leave a certain margin (5~10mm) to ensure that the fixed plate of the ejector pin does not hit the moving template or moving mold plate when it is completely ejected.

Determination of the overall structure of the mold frame

After the basic selection of the mold frame, the overall structure of the frame should be checked to see if the determined mold frame is suitable for the selected or customer-specified injection molding machine, including the size, thickness, maximum opening stroke, ejector mode, and ejector stroke of the mold frame shape.

Selection of insert material

Mold insert materials should have four main properties: ① hardness; ② wear resistance; ③ strength and toughness; ④ corrosion resistance.

The choice of insert material is mainly based on the batch of plastic products, plastic category to determine.

The products are general plastics such as ABS, PP, PC, and other plastics, usually choose model P20 and other types of pre-hardened tempered steel, if the batch of products is larger, should be selected quenched and tempered steel such as model H13.

High brightness or transparent plastic products, such as PMMA, PS, AS, and other plastics or plastics containing glass fibers are mainly used in model 420 and other types of corrosion-resistant stainless steel.

In addition to the above selection being accurate, several selection points must not know ↓↓↓

1, the mold thickness H and the closing distance of the injection machine L for different models and specifications of injection machines, different structural forms of clamping mechanisms have different closing distances.

2, the mold opening stroke and the distance between the fixed and dynamic mold separation and the required stroke to launch the plastic parts design, must be calculated to determine, the injection machine should be greater than the mold opening stroke required to take out the spacing between the fixed and dynamic mold separation, while the mold launch distance must be less than the rated ejector stroke of the injection machine ejector hydraulic cylinder.

3, the selected mold frame should be installed on the injection machine: the mold frame size should not be affected by the spacing of the injection machine tie bar; the positioning aperture and the positioning ring size should be well matched; the location of the ejector rod hole and the ejector stroke of the injection machine should be suitable; the nozzle aperture and sphere radius should be matched with the gate sleeve aperture and concave sphere size of the mold; the location and aperture of the mold frame mounting hole should be matched with the mobile template and the fixed template of the injection machine. The position and aperture of the mould frame mounting holes are compatible with the corresponding screw holes on the mobile mould plate and fixed mould plate.

To ensure the quality of the plastic parts and the performance and reliability of the mold, the mechanical properties of the mold parts, especially their strength and stiffness, should be accurately checked and calculated to determine the length, width, and thickness of the moving and fixed templates and support plates so that the specifications of the mold frame can be correctly selected.