Injection mold development process- Taizhou Huangyan Rongdu Mould Co., Ltd.

1. Drawing the mold map

Before drawing the general assembly drawing of the mold, the process drawing should be drawn, and the requirements of the part drawing and process data should be met. The size guaranteed by the next process should be marked with the words "process size" on the drawing. If no other machining is performed after forming except for repairing burrs, the process drawing is exactly the same as the part drawing. It is best to mark the part number, name, material, material shrinkage rate, drawing scale, etc. below the process diagram. Usually, the process is drawn on the mold assembly drawing.

The general assembly drawing should be drawn in a ratio of 1:1 as far as possible, starting from the cavity, and drawing the main view and other views at the same time.

The mold assembly drawing should include the following:

Mold forming part structure

Structural form of gating system and exhaust system.

Parting surface and parting pick-up method.

Outline structure and all connectors, positioning, the location of guides.

Mark the cavity height size (not mandatory, as needed) and the overall size of the mold.

Auxiliary tools (removal tools, calibration tools, etc.).

Serialize all the part numbers in sequence and fill in the schedule.

Mark technical requirements and instructions for use.

The technical requirements of the mold assembly drawing:

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

Requirements for mold assembly process. For example, after the mold is assembled, the bonding gap of the bonding surface of the parting surface should not be greater than the parallelism requirements of 0.05mm above and below the mold, and indicate the size determined by the assembly and the requirements for the size.

Mold use, assembly and disassembly method.

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

Requirements for mold testing and inspection.

The order of dismantling and drawing the parts drawing from the general assembly drawing of the mold should be: first inside and then outside, first complex and then simple, forming parts first, then structural parts.

Requirements are as follows:

graphics requirements

Be sure to draw to scale, allowing for zooming in or out. The view selection is reasonable, the projection is correct, and the layout is appropriate. In order to make the processing patent number easy to understand and easy to assemble, the graphics should be as consistent as possible with the general assembly drawing, and the graphics should be clear.

The dimensioning requirements are unified, centralized, orderly and complete

The order of dimensioning is as follows: firstly mark the size of the main parts and the draft slope, then mark the matching size, and then mark all the dimensions. On the non-main parts drawing, first mark the mating dimensions, and then mark all the dimensions.

Surface roughness

Mark the most applied roughness on the upper right corner of the drawing, such as "The rest 3.2." Other roughness symbols are marked on each surface of the part.

Other content

For example, part name, mold drawing number, material grade, heat treatment and hardness requirements, surface treatment, graphic scale, machining accuracy of free size, technical description, etc. must be filled in correctly.

2. Proofreading and reviewing drawings

The relationship between the mold and its parts and the drawings of plastic parts

Whether the material, hardness, dimensional accuracy and structure of the mold and mold parts meet the requirements of the plastic parts drawings.

plastic parts

Whether the flow of plastic flow, shrinkage holes, weld lines, cracks, demolding slope, etc. affect the performance, dimensional accuracy, surface quality and other requirements of plastic parts. Whether the pattern design is insufficient, whether the processing is simple, and whether the shrinkage rate of the molding material is selected correctly.

Forming equipment

Whether the injection volume, injection pressure, and clamping force are sufficient, whether there are problems with the installation of the mold, the south core of the plastic part, and the demoulding, whether the nozzle of the injection machine and the mouth sleeve are in correct contact.

Mold structure

Whether the position of the parting surface and the finishing accuracy meet the requirements, whether there will be overflow, and whether the plastic parts can be guaranteed to stay on the side of the mold with the ejector after the mold is opened.

Whether the demoulding method is correct, whether the size, position and quantity of the promotion rod and push tube are appropriate, whether the push plate will be stuck by the core, and will it cause scratches on the molded parts.

Mold temperature regulation. The power and quantity of the heater; whether the location, size and quantity of the flow line of the cooling medium are appropriate.

The method of dealing with the undercut made of plastic parts, whether the mechanism for removing the undercut is appropriate, for example, whether the slider and the push rod in the core-pulling mechanism of the inclined guide column interfere with each other.

The location and size of the pouring and exhaust systems are appropriate.

Design drawings

Whether the placement of each mold part on the assembly drawing is appropriate, whether it is clearly expressed, and whether there is any omission;

Part number, name, production quantity, internal or external purchase of parts, standard parts or non-standard parts, parts matching processing accuracy, correction processing and allowance at high-precision dimensions of molded plastic parts, mold parts on the part drawing Whether the material, heat treatment, surface treatment, and surface finish are marked and described clearly.

Main parts, working dimensions and matching dimensions of formed parts. The size numbers should be correct, do not make the manufacturer convert.

Check the view position of all parts drawings and general assembly drawings, whether the projection is correct, whether the drawing method conforms to the national drawing standard, and whether there are any missing dimensions.

Check Machining Performance

Whether the geometry, view drawing, dimensioning, etc. of all parts are conducive to machining

Main working dimensions of recalculation aids

In principle, professional proofreading is carried out according to the designer's self-proofing project; however, it should focus on structural principles, process performance and operational safety. When drawing, first digest the graphics, draw according to the requirements of the national standard, and fill in all the dimensions and technical requirements. Self-study and sign after tracing.

Submit the drawn base map to the designer for proofreading and signature. It is customary for the relevant technical personnel of the tool manufacturing unit to review, countersign and check the manufacturing process before sending it for drying.

Write Manufacturing Process Cards

The manufacturing process card is written by the technicians of the tool manufacturing unit and prepared for machining.

In the manufacturing process of mold parts, inspection should be strengthened, and the focus of inspection should be placed on dimensional accuracy. After the mold is assembled, the inspector will check according to the mold inspection table. The main thing is to check whether the performance of the mold parts is good. Only in this way can the manufacturing quality of the mold be guaranteed.

3. Trial and repair

Although the mold design is carried out under the expected process conditions when selecting molding materials and molding equipment, people's understanding is often imperfect. How is the quality. After the discovery is always made, repair the model to eliminate the error.

There are many types of bad phenomena in plastic parts, and the reasons are very complicated. There are reasons for the mold and the reasons for the process conditions. The two are often only combined.

Before repairing the mold, a detailed analysis and research should be carried out according to the actual situation of the bad phenomena in the plastic parts, and the remedy methods should be proposed after finding out the reasons for the defects of the plastic parts. Because the molding conditions are easy to change, the general practice is to change the molding conditions first, and only consider repairing the mold when changing the molding conditions cannot solve the problem.

Repairing the mold should be more cautious, and you should not act rashly if you are not very sure. The reason is that once the mold conditions are changed, major modifications and restorations cannot be made.

Whether the performance of the part is in good condition is the only way to slang for the manufacturing quality of the mold.

Fourth, organize data for archiving

After the mold is tested, if it is not used temporarily, the mold release residue, dust, oil, etc. should be completely wiped off, coated with butter or other anti-rust oil or anti-rust agent, and kept in the storage place.

From the design of the mold to the successful mold processing and inspection, the technical data generated during this period, such as task book, part drawing, technical specification, mold assembly drawing, mold part drawing, base map, mold design instruction, inspection record Forms, mold trial and repair records, etc., are systematically organized, bound, numbered and filed according to regulations. This seems like a lot of trouble, but it is very useful to repair the mold in the future and design a new mold.

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