The mold base of the mold generally uses standard mold bases and standard accessories, which is very advantageous for shortening the manufacturing cycle and reducing the manufacturing cost. The standard formwork used by most companies and manufacturers in China is Fudeba, Longji, Mingli and Tianxiang. In general, medium and small mold embryos can be selected from "Fu Deba", and larger mold embryos are often selected from "Long Ji", "Ming Li" or "Tianxiang". However, in actual production, it is often determined according to the price and structure of the mold and the complexity of the mold processing.
 
In case of special circumstances or customer specified requirements, the shape, size and material of the formwork can be changed, or the formwork can be completely redesigned. In this case, when ordering the formwork, it is required to provide the formwork supplier. Detailed mold frame drawing, and indicate the difference between the ordered formwork and the standard formwork.
 
1. Determination of the dimensions of the formwork and inserts
The size of the mold depends mainly on the size and structure of the plastic product. For the mold face, the more compact the structure, the better.
According to the product''s external dimensions (planar projected area and height) and the structure of the product itself (such as the structure of the lateral splitting slider), the outer dimensions of the insert can be determined. After determining the size of the insert, the formwork can be roughly determined. The size is up.
For the selection of mold dimensions and insert sizes for common plastic products, please refer to the following data:
“A”---- indicates the distance from the side of the insert to the side of the template.
“B”---- indicates the distance from the bottom of the fixed mold insert to the bottom surface of the fixed template.
“C”---- indicates the distance from the bottom of the movable mold insert to the bottom of the movable template.
“D”---- indicates the distance from the product to the side of the insert.
“E”---- indicates the distance from the highest point of the product to the bottom of the insert.
“H”---- indicates the thickness of the movable mold plate (when the mold frame is A type).
"X"---- indicates the height of the product.
  
The above data is only used as a reference for the general structural plastic product formwork. For special plastic products, the following points should be noted:
 
(1) When the product height is too high (product height X ≥ D), the "D" should be appropriately increased to increase the value △ D = (X - D) / 2.
(2) Sometimes in order to cool the waterway, the size of the insert should be adjusted to achieve a better cooling effect.
(3) When the structure is complicated, special type or ejector mechanism or lateral parting structure is required to make the slider. The size of the insert and the formwork and the thickness of each formwork should be adjusted according to different conditions to ensure the formwork. Strength of.
 
2. Determination of the height of the square iron
The height of the square iron should ensure a sufficient ejection stroke, and then leave a certain margin (5-10mm) to ensure that the thimble fixing plate does not hit the moving plate or the movable plate carrier when fully ejected.
 
3. Determination of the overall structure of the formwork
After the basic selection of the formwork, the overall structure of the frame shall be checked to see if the determined formwork is suitable for the selected or customer-specified injection molding machine, including the size, thickness, maximum mold opening stroke, and ejection of the formwork. Ways and ejecting trips, etc.
 
4. Selection of insert materials
There are four main aspects of the performance of the mold insert material: 1, hardness; 2, wear resistance; 3, strength and toughness; 4, corrosion resistance. The choice of mold insert material is mainly determined according to the batch size and plastic type of the plastic product.
The products are general plastics such as: ABS, PP, PC and other plastics. Usually, the type P20 and other types of pre-hardened quenched and tempered steel are used. If the batch size is large, the quenched and tempered steel such as model H13 should be used.
High-gloss or transparent plastic products, such as PMMA, PS, AS and other plastics or glass fiber-containing plastics are mainly selected from type 420 and other types of corrosion-resistant stainless steel.