Considering injection molding and looking for some help with going forward with it. Here are some great tips to help you make the right decision and do so.
- If you’re using a manual purge on materials that are sensitive to heat, plastechgroup.com advice to keep these things in mind:
When the process has finished, don’t empty the barrel. Doing so may result in the oxidation of the material. In fact, this can happen within 10 minutes.
Generally speaking, the temperatures should not be higher than the processing temperature of the material that is sensitive to heat.
- You should estimate what your barrel capacity is before purging. Knowing it is even better because this will allow you to control the amount of purge. Generally speaking, 1-3 barrels are enough. This lets you be in better control of inventory, while at the same time minimizing costs.
- There are three rules to follow if you’re using chemical purchases or mechanical purges:
- When purging, use maximum safe screw
- Also, while purging you should use maximum back-pressure
- While purging, make sure the screw is forward
- Always follow the manufacturer’s instructions when it comes to soaking times with this industrial equipment. In order for a chemical reaction to happen, it’s important that enough time has passed by. Generally speaking, 15-20 minutes is the typical time frame for soaking.
- When the maximum allowable temperature is reached, then purges will usually perform at their best. Just make sure you don’t exceed the recommended temperature. This can be found in the manufacturer’s guide.
- Some purging compounds are better than others when it comes to certain tasks. If one compound isn’t working that good, then switch to another.
- If there are stubborn deposits, then vary the screw speed. Starting and stopping can also aid in dislodging deposits that are too stubborn.
- After the barrel and the screw are clean, you’ll want to use another barrel, but only filled halfway with purging compound.
- Generally speaking, you don’t run the screw empty, regardless if you’re purging or not purging. If you run an empty screw, then oxygen may react with plastics being used, which can then result in decomposition. You should shut the machine down only with a full barrel that contains the right number of purging compounds.
- Some suppliers of purging compounds recommend that an empty barrel should be left at shutdown. This is why it is important to know whether or not the purge is chemical or mechanical. Knowing this means specific procedures can be followed.
