Ten steps of plastic mold design

First, accept the mission statement

The task of forming plastic parts is usually proposed by the parts designer, which reads as follows:

1. After examination of the formal parts drawings, and indicate the use of plastic grades, transparency and so on.

2. Plastic parts manual or technical requirements.

3. Production output.

4. Plastic parts samples.

Usually the mold design task by the plastic parts craftsman based on the task of forming plastic parts proposed, mold designers to plastic parts task book, mold design task book

Based on the design of mold.

Collection and finishing of the workpiece design, molding technology, molding equipment, machining and special processing of information to prepare for the design of mold use.

1. Digestion of plastic parts map, understand the use of parts, plastic parts of the craft, dimensional accuracy and other technical requirements.

For example, plastic parts in the appearance of the shape, color transparency, the performance requirements of what is the plastic parts of the geometric structure, tilt, inserts and other conditions are reasonable, weld marks, Shrinkage and other defects forming the degree of tolerance, with or without coating, plating, adhesive, drilling and other processing. Select the highest dimensional accuracy of plastic parts for analysis, take a look at estimates

Whether the tolerance of the type is lower than the tolerance of the plastic part, whether the plastic part can be shaped to meet the requirements. In addition, but also understand the plastics plasticizing and molding process parameters.

2. digesting process data, analysis of process tasks proposed by the molding method, equipment type, material specifications, mold structure type and other requirements are appropriate, can be implemented.

Molding materials should meet the strength requirements of plastic parts, with good fluidity, uniformity and isotropy, thermal stability. According to the use of plastic parts, molding materials should be full

Foot dyeing, metallization conditions, decorative properties, necessary elasticity and plasticity, transparency or the like, reflectivity, adhesiveness or weldability.

3. Determine the molding method - the use of direct pressure method, casting method or injection molding method.

4, choose molding equipment

According to the type of molding equipment to mold, it must be familiar with a variety of molding equipment performance, specifications, features. For example, the injection machine should be aware of the specifications

The following: injection capacity, clamping pressure, injection pressure, mold installation size, ejector device and size, nozzle hole diameter and nozzle radius, sprue sleeve positioning ring size, The maximum thickness of the mold and the minimum thickness, template stroke, see the specific parameters.

To preliminary estimate the dimensions of the mold, to determine whether the mold can be installed on the selected injection machine and use.

5 specific structural programs

(1) to determine the type of mold

Such as the pressure die (open, semi-closed, closed), casting die, injection mold and so on.

(2) to determine the main type of mold structure

Select the ideal mold structure is to determine the necessary molding equipment, the ideal number of cavities in absolutely reliable conditions to enable the mold itself to meet the work of the plastic parts of the process

Technical and production economy requirements. The technical requirements of the plastic parts is to ensure that the plastic parts of the geometry, surface finish and dimensional accuracy. Production economy is the need to

The plastic parts of the low cost, high production efficiency, the mold can work continuously, long life, save labor.

Third, the impact of mold structure and die a number of individual system factors, is very complicated:

1. Cavity layout. According to the geometric features of plastic parts, dimensional accuracy requirements, batch size, mold manufacturing difficulty, mold cost, etc. to determine the number of cavities and their arrangement.

2. To determine the parting surface. The location of the sub-surface should be conducive to mold processing, exhaust, demoulding and molding operations, the surface quality of plastic parts.

3. Determine the gating system (main runner, sub-runner and gate shape, location, size) and exhaust system (exhaust method, exhaust slot location, size).

4. Select the top of the way (ram, pipe jacking, pushing the board, the combination of ejection), determine the concave treatment, the core pulling method.

5. Determine the cooling, heating and heating cooling groove shape, location, heating element installation site.

6. According to the mold material, strength calculation or empirical data to determine the thickness of die parts and dimensions, shape and structure of all connections, positioning, guide position.

7. Determine the main molding parts, structural parts of the structure.

8. Considering the strength of each part of the mold, calculate the working dimensions of the molded parts.

If these problems are solved, the structure of the mold will be solved naturally. At this time, you should start to sketch the structure of the mold, ready for the official drawing.

Fourth, draw the mold map

Requirements in accordance with the national cartographic drawing standards, but also requires the combination of factory standards and the state does not provide the factory custom painting.

Draw the mold assembly diagram, should draw the process diagram, and to comply with parts drawings and process data requirements. By the next process to ensure the size should be marked on the map marked "Craft ruler Inch. "If the burrs are not repaired after forming, no other machining is done, so the process drawings are the same as the parts drawings.

In the process diagram below the best marked part number, name, material, material shrinkage, draw ratio and so on. Usually put the process drawing in the mold assembly drawing.

Drawing assembly diagram

Draw the final assembly diagram as much as possible the use of 1: 1 ratio, the first drawing by the cavity, the main view and other views at the same time draw.

Five, mold assembly diagram should include the following:

1. Mold forming part of the structure

2. Gating system, exhaust system structure.

3. Parting surface and the way to take pieces.

4. Shape and structure of all connectors, positioning, the location of the guide.

5. Mark the height of the cavity size (not demanding, according to need) and the overall size of the mold.

6. Auxiliary tools (pick-unloading tools, calibration tools, etc.).

7. Make all part numbers in sequence, and fill in the schedule.

8. Mark the technical requirements and instructions for use.

Sixth, the technical requirements of the mold assembly diagram content

1. For mold some system performance requirements. For example, the ejection system, the slider core structure assembly requirements.

2. Mold assembly process requirements. For example, the fitting surface of the fitting surface of the parting surface after the mold assembly should not be larger than 0.05mm, the parallelism requirements on the upper and lower surfaces of the mold,Assembly dimensions and size requirements.

3 mold use, demolition methods.

4. Anti-oxidation treatment, mold number, lettering, marking, oil seal, custody and other requirements.

5. Test and test requirements.

Seven, draw all the parts map

Drawing from the assembly diagram of the drawing assembly drawing order should be: the first inside and outside after complex first simple, first molding parts, after the structural parts.

1. Graphic Requirements: Be sure to draw in proportion to allow zoom in or out. The view is reasonable, the projection is correct, well-arranged. In order to facilitate the processing of patent number easy to understand, easy assembly, Graphics as much as possible with the assembly diagram, graphics should be clear.