General steps of forming part design

The first step is to determine the number of cavities;

The second step is to determine the Parting Line (Parting Line);

The third step is to determine the parting surface,

The fourth step is to determine whether to pull the core laterally according to the plastic parts;

Step 5 Calculate the molding size of the core cavity and determine the draft angle;

The sixth step is to rank and determine the size of the inner mold insert;

The seventh step is to determine the combination and fixing methods of the molded parts.

The first step is to determine the number of cavities:

(1) Determine the number of cavities according to the batch of products.

If the product batch is small, the number of molds should be reduced as much as possible to reduce costs. At this time, it is advisable to arrange the plastic parts with the same variety, inter-color, and small volume in the same mold for production. If the product is in large batches, try to arrange the same plastic part to be produced in the same mold, that is, one mold has multiple cavities, and each cavity is the same.

(2) Determine the number of cavities according to the accuracy of the plastic parts.

If the precision of the plastic parts is high, the smaller the number of cavities, the better, and generally should not exceed 4 cavities. The number of mold cavities with general accuracy should not exceed 24 cavities.

(3) Determine the number of cavities according to the size of the plastic part.

The size of the plastic part also directly affects the number of cavities per mold. Larger plastic parts should have one mold and one cavity; small plastic parts should have one mold and multiple cavities, but the mold should not be too large, and the length and width dimensions should not be larger than 300¡Á400 (MM)

(4) Determine the number of cavities according to the material and color.

Plastic parts produced by the same mold generally have the same plastic varieties and the same color.

(5) The method of determining the number of cavities according to the size of the injection molding machine.

¢ÙIf the injection molding machine matching the mold is determined in advance, then: (total weight of the plastic parts in each cavity + weight of the condensate of the pouring system) ¡Ü rated injection volume of the injection molding machine¡Á80%

¢Ú If the injection molding machine that matches the mold is not determined, the size and quantity of the mold in a set of products must be balanced, each accounting for a certain proportion.

The first step is to determine the number of cavities:

(1) Determine the number of cavities according to the batch of products.

The second step is to determine the par firtg line (Par firtg Line):

The parting line is the dividing line that divides the product into two parts, the front mold and the back mold.

The third step is to determine the parting surface:

The parting line extends around the mold core to obtain the parting surface.

In the mold, the separable contact surface that can take out the product or the nozzle is called the parting surface (or parting surface).

General principles for determining the parting surface:

1. Conducive to demolding:

(1) After the mold is opened, the plastic parts should be left on the side with the ejection mechanism, usually on the movable mold;

(2) Conducive to side parting: make the core-pulling distance the shortest.

2. Easy to process: can be divided into planes but not inclined; can be divided into inclined planes but not curved

3. It helps to ensure the precision of plastic parts.

4. Easy to install the inserts.

5. Guarantee the appearance quality.

6. The parting surface must not have sharp corners.

7. The parting surface should be positioned when parting on inclined surface or curved surface.

The fourth step is to determine whether to pull the core laterally according to the plastic part

The fifth step is to calculate the molding size of the core cavity and determine the draft angle

The sixth step is to rank and determine the size of the inner mold insert

1. General principles of ranking:

1) Ensure the pressure balance of the mold.

2) Ensure the temperature balance of the mold.

3) Ensure the feed balance of the mold.

4) The runner of the gating system is the shortest.

5) The length and width of the inner mold insert are coordinated, and the width is the smallest.

2. The ranking determines the size of the insert

First, determine the length and width of the inner mold insert (mold core):

(1) The steel position B between each cavity is 12~20mm,

? In special cases, it can be 20~30mm.

? Special circumstances:

One piece of plastic is larger and deeper;

One insert set through;

One water input (feeding) is latent water input (feeding), etc.

(2) The steel level A from the cavity to the edge of the inner mold insert is related to the depth of the cavity. The following table is the empirical value:

When designing the mold, the size of the mold core (insert) must be an integer and a standard number.

Secondly, determine the thickness of the inner mold insert:

(1) The thickness of the front mold (fixed mold) insert = cavity depth + (15-20) mm;

(2) The thickness of the back mold (moving mold) insert = the depth of the glue position + (15~30)mm;

Note: The thickness must be determined to ensure that the mold has sufficient strength and rigidity.

The seventh step is to determine the combination and fixing methods of the molded parts.