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What is the standard development process of the injection mold?
- Jul 24, 2018 -

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1. Drawing die drawing

Before drawing the general assembly drawing, draw up the process diagram and conform to the requirements of the parts drawing and process information. For the size guaranteed by the next process, the word "process dimension" should be marked on the drawing. If there is no other machining process besides shaping the burrs, then the process diagram is exactly the same as the part drawing.

Under the process chart, the number, name, material, material shrinkage, drawing proportion and so on are best marked. The working procedure is usually painted on the mold assembly drawing.

Draw the general assembly drawing as far as possible, using the ratio of 1:1, first draw the cavity, and draw the main view with other views at the same time.

The mold assembly drawings should include the following:

Mold forming part structure

The structure of the pouring system and the exhaust system.

Parting surface and mold drawing method.

Exterior structure and all connectors, location and orientation.

Dimensioning cavity height (not forced, as required) and mold overall size.

Auxiliary tools (removing tools, correcting tools, etc.).

Compile the serial numbers of all parts in order and fill in the detailed list.

Mark technical requirements and use instructions.

Technical requirements of mold assembly drawings:

Performance requirements for certain systems of the mold. For example, the assembly requirements of ejection system and slider core pulling structure.

The requirements for the die assembly process. For example, the closing surface of the mold assembly surface after the die assembly is not greater than the parallelism requirements on the 0.05mm mold and below, and points out the size determined by the assembly and the requirements for the size.

The use of the mould and the method of assembly and dismantling.

Anti oxidation treatment, mold number, lettering, marking, oil seal, storage and other requirements.

Requirements for test and inspection.

The sequence of drawing the part drawing from the general assembly drawing of the die should be as follows: first, inside and outside, first complex and then simple, first forming parts, then structural parts.

The requirements are as follows:

Graphic requirements

It must be painted in proportion, allowing for enlargement or reduction. The choice of view is reasonable, the projection is correct and the layout is proper. In order to make the processing patent number easy to understand and easy to assemble, the graphics should be consistent with the assembly drawing as far as possible, and the graphics should be clear.

Requirements for dimensioning are uniform, centralized, orderly and complete.

The order of dimensioning is as follows: first, mark the size of the main parts and the slope of the mould, then mark the matching dimensions, and then mark all the dimensions. The size of the main parts should be labeled together and all dimensions should be marked.

Surface roughness

Mark one of the most applied roughness to the top right corner of the drawing, for example, mark the remaining 3.2. "Other roughness symbols are marked on each part of the part.

Other content

For example, part name, mold number, material brand, heat treatment and hardness requirements, surface treatment, graphics ratio, the processing precision of free size, technical specification and so on should be correctly filled.

Two, proofreading and drawing

The relationship between the mould and its parts and the drawing of the plastic parts

The material, hardness, dimensional accuracy and structure of the die and mold parts conform to the requirements of the plastic drawing.

Parts of plastic parts

Whether the flow of plastic flow, shrinkage hole, weld mark, crack, stripping angle and so on affect the use performance, size accuracy and surface quality of plastic parts.  Whether the design is inadequate, whether the processing is simple, whether the shrinkage of the molding material is selected correctly.

Forming equipment

The injection amount, the injection pressure and the clamping force are not enough. There are no problems with the installation of the mold, the South core and the mold release of the plastic parts.

Die structure aspect

Whether the position of the parting surface and the precision of precision machining meet the needs will not occur, and the plastic parts can be kept on the side of the mold with the ejector device after the die opening.

Whether the demoulding mode is correct, the size, position and quantity of the extension rod and tubing are suitable, and the push board will not be stuck by the core, and will not cause the scraping parts.

Mould temperature regulation. The power and quantity of the heater, the location, size and quantity of the flow line of the cooling medium are suitable.

The method of processing the side concave of plastic parts, whether the mechanism of removing the side concave is appropriate, such as whether the slider and the push rod in the core pulling mechanism of inclined guide column interfere with each other.

The position and size of the pouring and exhaust system are appropriate.

Design drawings

Whether the placement parts of the die parts are properly displayed on the assembly drawings, whether they are clear and omissions;

The number and name of parts, the name of the parts, the quantity, the internal system or the purchase, is the standard or non standard parts, the accuracy of the parts and the accuracy of the parts, the corrected processing and remainder of the high precision size of the molded parts, and the marking and narration of the material, heat treatment, surface treatment and the degree of surface finishing of the mold parts. It is clear.

Working dimensions and matching dimensions of main parts and forming parts of parts. The size number should be correct and do not convert the producer.

Check the location of all parts and assembly drawings, whether the projection is correct, whether the drawing is in line with the national standard for drawing, and whether there is a missing size.

Checking processing performance

Is the geometric structure, view drawing and size label of all parts conducive to processing?

The main working dimensions of the auxiliary tools

Professional proofreading is carried out in accordance with the designer's self proofreading project, but it should be focused on structural principles, process performance and operational safety. When digesting the figures, we should depict and fill in all the dimensions and technical requirements according to the requirements of the national standard. Write and sign after drawing.

The drawing of the bottom map is given to the designer to proofread the signature. The customary practice is to check, check and inspect the manufacturing process by the technical personnel of the tool manufacturing unit.

Write a manufacturing process card

The manufacturing process card is prepared by the technician of the tool manufacturing unit, and is prepared for manufacturing.

In the manufacturing process of mold parts, inspection should be strengthened and emphasis should be placed on dimensional accuracy. After the mold assembly is completed, the inspector is inspected according to the mold inspection table. The main thing is to check the performance of the die parts well. Only in this way can the quality of the mould be ensured.

Three, test mold and mold repair

Although it is in the selection of molding materials and molding equipment, the mold design is carried out under the preconceived technological conditions, but people's understanding is often imperfect, so it is necessary to test the mold after the die processing is completed and see how the quality of the moulded parts is. Always after the discovery, to eliminate errors in the mold repair.

There are many kinds of bad phenomena in the plastic parts, and the reasons are very complicated. There are reasons for the mold and the reasons for the technical conditions. The two are often only together.

Before repairing the mould, we should make a detailed analysis and study according to the actual situation of the defective phenomena appearing in the plastic parts, and find out the remedy after the cause of the defect of the plastic parts. Because the molding conditions are easy to change, the general practice is to change the molding conditions first. When changing the molding conditions can not solve the problem, then consider repairing the mold.

It is more prudent to repair moulds. The reason is that once the mold conditions are changed, no major transformation and restoration can be made.

The performance of parts is good, only in this way can slang mold manufacturing quality.

Four. Filing data for archiving

If the mold is not used for the time being, the mold should be completely erased, such as dregs, dust, oil, etc., coated with butter or other antirust oil or antirust agent, and kept in the storage place.

The design mold begins to the successful process of the mold processing, the inspection is qualified so far, the technical data produced during this period, such as the task book, the piece drawing, the technical specification, the mold assembly drawing, the mold parts drawing, the bottom drawing, the mold design instruction, the inspection record table, the test model repair and recording, etc., are systematically arranged and installed according to the regulations. Order and number for filing. It seems very troublesome to do this, but it is very useful for repairing moulds and designing new moulds later.