Injection moulding Design

The Procedures You Can Use For Injection Mold Maker

One of the most important parts in processing plastic is using a perfect mold that you will use to give shape to the product. There are some manufacturers that have their own tools that can quickly create shape into the mold. Although there are already available machines for injection mold making, it is still an additional challenge to create your own design. Becoming a skilled mold designer will require intensive training and of course practice. If you are interested in this kind of profession you will have to learn it from the experts.

With the wide effect of the technology in our market today it is not impossible that there are already available machines that can be used in injection mold making. However, if you love challenges and like to learn how to do it, you can start from drafting your design. This way, you will know the details that need to be added to the design. This is important in injection mold making because it is where your product will be based from. If there’s a single error in the measurement of the draft it will affect the whole process. Another important part that you must consider is to know the material that you like to use. It is advisable to choose ones that cannot affect the products output. You can start creating a design that has simple shape until you master it and create a more complicated design.

Injection mold making is very important when it comes to injection molding because this is where the entire product will be judged on. If the mold has good quality, the result will also be at its best that will also result to your company’s success.

Injection mold making must be done seriously because it is the key to the success of the company. If there’s single mistake from the making of the mold the whole process will be ruined and you will have to start it again.

There are two areas of consideration in designing for injection moulding

Production Considerations

Plastic Injection moulding is a heat process and plastics are poor conductors of heat, that is to say it takes a relatively long time for plastic parts to cool down. With this in mind the aim should be to keep sections of parts as thin as possible, this will not only mean shorter moulding cycle times but also less material content.

Strength – If the part needs some strength this can be achieved by the addition of ribs rather than thickening of the section. With plastics, thicker sections do not necessarily mean stronger parts, in some instances beyond a certain thickness the part can become more brittle due to the resulting lack of flex.

Material– Another consideration is choice of material type and grade. Thermoplastics can range in price from just over £1 per kg for basic polyolefins up to £25 per kg and beyond for PEEK and other specialised polymers. By designing strength into a part it may be possible to use a cheaper material but sometimes the reverse can be true and advice should be sought from the moulder.

The price of polymers is also governed to a certain extent by the amount purchased so some benefit may be gained by using a grade already used by the moulder. Be guided by the moulder rather than sticking rigidly to a specified grade.

Eliminate Assembly– If a number of parts are required, and especially when converting from metal or a different production method, look at the possibilities of combining two or more parts into a single moulding so eliminating assembly. It is often possible to produce complex single mouldings that would not be possible with a different method of production. In a similar vein, where assembly is required every effort should be made to make this as simple as possible with the use of snap-fits, for example.

Tooling Considerations

Combining Parts – Injection molding molds is relatively expensive but it is not always correct to assume that it is only suited to long production runs. If it is possible to combine a number of parts into a single moulding, for example, then the cost of assembly and possible other ancillary parts can be saved making shorter production runs economical.

Keep it Simple– The simpler the mould tool the lower the cost. If possible avoid holes in side walls of parts, undercuts and other complex features. The mould tool can then be what is referred to as straight open and close. If the part does need side holes, for example, then these can either be moulded in which would require side movements in the mould tool, or a secondary operation will be necessary. Which approach is adopted will depend on anticipated quantities of the part – the higher the number of parts required the more economical it is to have the features produced by the mould tool rather than as a secondary operation.

The same rule applies to threads. Internal threads can of course be tapped afterwards but the usual method is to have them moulded in. This can be achieved in two ways, either with hand loaded cores or with auto unscrewing in the mould tool. The former requires operator intervention during the moulding process so adding to the part cost whereas the latter means the mould tool can be run fully automatically but will mean a higher tooling cost at the outset.

Multiples– To reduce both total tooling and part costs where a number of similar parts are required in equal quantities and in the same material, it may be possible to produce a family tool, i.e. all the parts moulded in a single cycle from a single tool. Also, where large quantities of a part are required, a multiple cavity tool could be used, i.e. two or more of the same part produced in a single cycle. Although the tooling cost would be higher than for a single impression tool, the part price will be lower so making it cost effective. The moulder can advise on the optimum configuration.

Conclusion

There are a number of factors that impact upon part and tooling cost: material selection, the section of the part, the complexity of the design, etc. What is certain is that the further down the design/production cycle you are the more costly any alterations become. Therefore, it is advisable to get the initial design right for injection moulding and to this end, you should involve your injection moulder at the very early stages of the project to ensure correct design and material selection for the given application.

Injection Mold Making