What do you need to know about the important aspects of the mold from design to mold trial?

1. Drawing mold diagram

Before drawing the general assembly diagram of the mold, the process diagram should be drawn and conform to the requirements of the part-making diagram and injection molding process information.

The dimensions guaranteed by the next injection molding process should be marked on the drawing with the words ‘process dimensions’. If there is no mechanical processing after molding except for burr repair, the process diagram is identical to the part drawing.

It is better to mark the part number, name, material, material shrinkage rate, drawing ratio, etc. below the process drawing, and usually, the mold making process drawing is drawn on the general assembly drawing of the mold.

Draw the general assembly structure

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

The general assembly drawing of the mold should include the following contents.

(1）The structure of the molding part of the mold.

(2) The structure form of the pouring system and exhaust system.

(3）The parting surface and the way of taking parts from the mold.

(4) The shape structure and the position of all connecting parts, positioning, and guiding parts.

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

(6) Auxiliary tools (picking and unloading tools, calibration tools, etc.).

(7) All the parts to number out, and fill out the detailed list.

(8) Mark the technical requirements and instructions for use.

The technical requirements of the general assembly drawing of the mold include:

(1) For the performance requirements of some systems of the mold. For example, the assembly requirements for the ejector system and core pulling structure of the slider.

(2) Requirements for the mold assembly process. For example, the fitting gap of the fitting surface of the parting surface after mold assembly should be no more than 0.05mm.

The parallelism requirement of the upper and lower part of the mold, and point out the size decided by the assembly and the requirement of the size.

(3) Mold use, assembly, and disassembly method.

(4) Anti-oxidation treatment, mold numbering, lettering, marking, oil seal, storage, and other requirements.

(5) Requirements concerning mold testing and inspection.

Draw all parts diagram

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

(1) Graphic requirements: Must be drawn to scale, allowing enlargement or reduction. The view selection is reasonable, the projection is correct, and the arrangement is appropriate. To make the processing patent number easy to read, easy to assemble, and graphics as far as possible with the general assembly drawings, graphics should be clear.

(2) Labeling dimensions require uniformity, concentration, order, and completeness. The order of labeling dimensions: first mark the size of the main part and out of the mold slope, then label with the size, and then label all dimensions. The non-major parts of the diagram are first marked with the size and then marked with all the dimensions.

(3) Surface roughness： The application of the most roughness is marked in the upper right corner of the drawing, such as marked ‘the rest of 3.2.’ Other roughness symbols in the parts of each surface are marked.

(4) Other content, such as the name of the part, mold drawing number, material grade, heat treatment, and hardness requirements, surface treatment, graphic proportions, free dimensions of machining accuracy, technical descriptions, etc. should be filled out correctly.

Proofreading, reviewing, tracing, sending to the sun

(1) The relationship between the mold and its parts and the drawing of the plastic parts

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

(2) Plastic parts

Whether the flow of plastic material flow, shrinkage, fusion marks, cracks, mold slope, etc. affects the performance, dimensional accuracy, surface quality, and other requirements of the plastic parts.

The pattern design has no shortcomings, the processing is simple, and the shrinkage rate of the molding material is selected correctly.

(3) Molding equipment

The injection volume, injection pressure, and clamping force are enough, the installation of the mold, the southern core of the plastic parts, and the mold release have no problems, and the injection machine nozzle and the querulous sleeve are correctly contacted.

(4) Mold structure

1. Whether the position of the parting surface and finishing accuracy meet the needs, whether overflow will occur, and whether the plastic parts can be guaranteed to stay on the side of the mold with the ejector device after opening the mold.

2. Whether the mold release method is correct, whether the size, position, and number of the promotion rod and push tube are suitable, whether the push plate will be stuck by the core, and whether it will cause abrasion to the molded parts.

3. In terms of mold melt temperature adjustment. The power and quantity of the heater; whether the location, size, and quantity of the mold flow analysis line of the cooling medium are suitable.

4. The method of dealing with the side concave of the plastic parts system, whether the mechanism of removing the side concave is appropriate, for example, whether the slider and the push rod in the inclined column mold core extraction mechanism interfere with each other.

5. The location of the pouring and exhaust system, and whether the size is appropriate.

(5) Design drawings

1. Assembly drawings on the injection mold parts placement parts are appropriate, whether the representation is clear, there is no omission.

2. Parts number, name, mass production process quantity, parts made or purchased, standard parts or non-standard parts, parts with processing accuracy, molding plastic parts with high precision size correction processing and allowance, mold parts material, heat treatment, surface treatment, surface finishing degree is marked, clear description.

3. Parts of the main parts, molding parts working size, and fit size. Size figures should be correct, do not make the producer convert.

4. Check the view position of all parts and the general assembly diagram, whether the projection is correct, whether the drawing method is in line with the national standard of cartography, and whether there is no omission of dimensions.

(6) Check the processing performance

All parts of the geometric structure, view drawing, size scale ‘and so on are conducive to processing.

(7) Recalculate the main working dimensions of auxiliary tools

(1) Professional proofreading in principle according to the designer’s self-calibration project; but focus on structural principles, process performance, and operational safety aspects.

When digesting the graphs, fill in all dimensions and technical requirements according to the national standard requirements. After the drawing, self-calibrate, and sign.

(2) The tracing of the base map to the designer to proofread and sign, the customary practice is to be reviewed by the relevant technical personnel of the tool manufacturing unit, countersign, check the manufacturing process, and then can be sent to the sun.

(8) Preparation of manufacturing process card

In the tool manufacturing unit technical personnel prepare the manufacturing process card, and are ready for processing and manufacturing.

In the manufacturing process of mold parts strengthen the inspection, the focus of the inspection is dimensional accuracy.

After the mold is assembled, the inspector will inspect it according to the mold inspection table, the main thing is to check whether the performance of the injection mold parts is good or not, only in this way can the manufacturing quality of the mold be guaranteed.

Mold test and mold repair

Although it is in the selection of molding materials, molding equipment, and mold design under the expected process conditions, people’s understanding is often imperfect, so must be completed in the mold processing, and mold trial test, to see how the quality of injection molded parts. After finding always, carry out the mold repair to exclude the error nature.

There are many kinds of defective plastic parts, and the reasons are very complicated, there are reasons for the mold, and there are also reasons for the process conditions, the two are often crossed together.

Before repairing the mold, we should analyze and study the defect in detail according to the actual situation of the molded part, find out the cause of the defect and propose remedial methods.

Because the molding conditions are easy to change, so 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.

Repair the mold should be more cautious, not very sure not to take rash action. The reason is that once the mold conditions are changed, it is not possible to make a major transformation and restore the original state.

The performance of the parts is good, only then can slang language mold manufacturing processes quality.

Organize information for archiving

After the test, if the mold is not used for a while, it should be completely wiped off the mold dross, dust, oil, etc., coated with butter or other anti-rust oil or anti-rust agent, and off to the storage place for safekeeping.

From the beginning of the design of the mold to the successful processing of the mold, inspection, the technical data generated during this period, such as the mission statement, parts drawing, technical specifications, mold assembly drawings, injection mold parts drawings, base drawings, mold design instructions, inspection record sheets, mold repair records, etc.

According to the provisions of the system to organize, binding, numbering for archiving. This seems to be very troublesome, but it is useful for repairing molds and designing new molds in the future.