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Common problems and precautions in plastic molds making

Posted by: Mu Ju 2021-12-02 Comments Off on Common problems and precautions in plastic molds making

The production process of a set of plastic molds is not a one-step process. It is necessary to grasp the structural design of the product well, so as to avoid many problems in the subsequent production process, such as shrinking and flashing.
So, what issues should you pay attention to when making molds?

Don’t just focus on product design and neglect mold manufacturing

Some users just focus on product development when developing products or testing new products, always neglect communication with mold maker.
After the plan of product design is initially determined, there are three benefits to contacting the mold manufacturer in advance:

  1. It can ensure that the designed product has a good forming process and will not modify the stereotyped design because the part is difficult to process.2, the mold maker can make design preparation in advance to prevent ignorance in the inconsistency, affecting the construction period.

    3, the production of high-quality molds, only the supply and demand cooperate closely, then can reduce costs and shorten the cycle ultimately.

Don’t just concern the price, we must consider all aspects of quality, cycle time and service:

1. There are many types of molds, which can be roughly divided into ten categories.
According to the different requirements of parts materials, physical and chemical properties, mechanical strength, dimensional accuracy, surface finish, service life, economy, etc., different types of mold forming are selected.

2. The mold with high precision requires the use of high-precision cnc machine tools, and the mold material and forming process have strict requirements. CAD / CAE / CAM mold technology is also needed to design and analyze.

3, some parts have special requirements due to molding, the mold also needs to use hot runner, gas-assisted molding, nitrogen cylinder and other advanced technology.

4, manufacturers should have CNC, EDM, wire cutting machine and CNC copy milling equipment, high-precision grinding machine, high-precision three-coordinate measuring instrument, computer design and related software.
5, the general large-scale stamping dies (such as automotive cover parts mold) should consider whether the machine tool has a crimping mechanism, and even side lubricants, multi-station grade and so on.
In addition to punching tonnage, it is necessary to consider the punching, feeding device, machine tool and mold protection device.

6. The manufacturing methods and processes of the above molds are not available and mastered by every enterprise.
When choosing a collaborative manufacturer, you must understand its processing capabilities, not only look at hardware equipment, but also combine management level, processing experience and technical strength.

7, for the same set of molds, different manufacturers sometimes have a big gap.
You should not pay more than the cost of the mold, and should not be less than the cost of the mold.
Mold manufacturers, like you, have to make a reasonable profit in the business.
Ordering a set of molds with much lower quotations can be a hassle to start.
Users must proceed from their own requirements and comprehensively measure them.

Avoid multi collaboration, try to make mold and product processing in one-stop:

Precautions in the processing of plastic molds:

1. The shrinkage coefficient of each material is different, and the plastic mold should have a reasonable shrinkage rate.

2. The plastic mold should have sufficient rigidity, otherwise it will be deformed when the mold is kept under pressure, causing “flash”.

3. If the product is opened while the mold is being opened, the ejector page of the injection molding machine can be set (but some injection molding machines do not have this function).

4. Choose a reasonable demoulding method and choose a reasonable position and quantity of the ejector to ensure that the product is not damaged during the ejection process.

5. The cooling (water passage) in the plastic mold is related to factors such as product size, shape, plastic properties, and holding time.

6, plastic mold to choose a reasonable position of the exhaust and its amount of control.
Otherwise, the plastic is not filled and the product is “lack of material”.

7. The fixing method of the plastic mold and the injection molding machine should be reasonable, and it must be reliable and firm, and prevent accidents caused by the displacement of the mold.
And it is easy to disassemble.

8. The plastic mold moves with the injection molding machine together with the moving part without the return spring. It is the mold ejector plate and the machine ejector pin (commonly known as the strong top).

9. The injection channel should be selected reasonably so that the material can reach every place evenly (the flow path is equal), and there must be sufficient storage to ensure that the plastic is replenished during the shrinking process.

10. Post-treatment of plastic mold materials is not required because: plastic is soft, no special requirements such as hardness are required, and the heat treatment process may cause deformation of the mold.

11. The roughness level of the plastic mold cavity should reach the “mirror level”, otherwise the product should be demoulded, and the product should be too strong to cause product damage when the product is ejected.
The roughness of the locating pin, the clamping surface and other parts are standard.

In summary, in the process of making the mold, the design of the product cannot be emphasized, and the production of the mold is neglected.
Once the mold appears any problems, it will directly affect the injection molding of the product, which directly affects the quality and delays the delivery time of the product.
Therefore, in the early stage of making plastic molds, the customer and the factory engineers should better communicate the products in order to achieve the best mold manufacturing.

About PTJMould Industrial Company Limited

PTJmould is a China mold maker of plastic molds- injection mold, die casting moulds, plastic blow molding, rotational molding, medical plastic injection molding, two shot plastic injection molding, insert molding, overmolding, metal injection molding, micro injection molding, powder injection molding, ceramic injection molding, liquid injection molding, husky injection molding, household mold, casting mold, die mold tool, custom molds, china moulds, rapid prototyping tooling, plastic prototyping tooling, punch press tooling, die and tooling for mobile/ cell phone parts, automotive parts, vacuum cleaners, rechargeable tools, telephones, copiers, computers, multimedia speakers, and many other electronic products and household appliances. And also a plastic product manufacturer, mold manufacturer China– plastic parts, plastic water tank, plastic balls, plastic containers, plastic buckle, plastic anchor, plastic hanger, plastic spoon, plastic pipe fitting, plastic tumble, plastic tableware, plastic cups, plastic bottles, plastic tray, plastic cosmetic container, plastic case, plastic food container, plastic chairs, plastic caps, plastic cap closure, plastic tubes, plastic water pipes, plastic knobs, plastic tubing, plastic utility boxes, plastic racks and so on.

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