Cleaning Methods For Injection Moulding Machine Screws And Barrels

Cleaning Methods For Injection Moulding Machine Screws And Barrels


In the realm of injection molding, the efficiency and quality of production heavily rely on the condition of the machine components, specifically the screws and barrels. During the production process, the inside of the machine needs to be cleaned due to changes in process conditions and materials. For example, it is common to change the colour of the material, to switch between different materials, or to accumulate dirt and black carbon deposits inside the machine. So how do you clean the screw of an injection moulding machine?

Use of The Correct Heating Device

The use of fire or baking to remove plastic embedded in the screw is the most common and effective method of plastic processing equipment, but acetylene flames should not be used to clean the screw. Acetylene flames can reach temperatures of up to 3000°C. Using an acetylene flame to clean a screw will not only damage the metal properties of the screw, but will also significantly affect the mechanical tolerances of the screw.

If the acetylene flame turns permanently blue when burning a part of the screw, it means that the metal structure of that part of the screw has been changed, which will lead to a reduction in the wear resistance of that part and even to the peeling of the anti-wear layer from the base metal. In addition, partial heating with an acetylene flame can cause overheating on one side of the screw, which can cause the screw to bend. Most screws are manufactured from 4140.H.T. steel to very tight tolerances, generally within 0.03mm.

The straightness of the screw is usually within 0.01mm. When the screw is baked and cooled with an acetylene flame, it is often difficult to return to its original straightness. The correct and effective way to clean the screw is to use a torch immediately after use. The heat distribution of the screw will still be uniform as the screw will then carry the heat from the process.

A Practical Guide to Injection Molding Plastics Engineering (3)

Use the Right Detergent

Plastics should not be used to clean machinery, let alone replace screw cleaners. Cleaning the screw with new plastic or recycled material is time consuming, wasteful and does not effectively remove pigments and carbonised contaminants.

There is a wide range of screw cleaners on the market, most of which are expensive and of varying effectiveness. Whether to use commercial cleaners, depending on different manufacturers and production; plastics processing companies can also be based on their own production, the use of different resins to do screw cleaning material, can save a considerable amount of money for the unit.

If the main cleaning screw paste, carbon, you should choose the physical method in the high glass fibre content of the cleaning agent; if you need to clean the hot runner or the production of transparent products, you should choose the hot runner special type or transparent material special type of cleaning agent. Read more about best injection moulding machine.

Use the Correct Machine Settings for Cleaning

To ensure that the screw is thoroughly cleaned, the moulding plastic machine settings recommended by the screw cleaner supplier should be followed throughout the cleaning process to ensure maximum effectiveness of the cleaner.

For example, one brand of screw cleaner requires the use of maximum safety screw speed and maximum safety back pressure during the cleaning process, so that the screw is always held in the forward position during cleaning and when using new plastic materials for replacement.

Good Machine Sealing During Downtime

In addition to regular and preventive maintenance cleaning, a heat-stable screw cleaner should be used to seal bearings during downtime, especially at weekends or holidays. During downtime, oxygen in the cylinder can cause residual polymer degradation and carbonisation, resulting in extended machine downtime or even scrapping. A screw cleaner is a good way to protect the screw and barrel from contamination during downtime and to get the injection moulding machine back into production mode quickly after the holidays.


Here we are at the end of our thrilling journey through the world of cleaning methods for injection moulding machine screws and barrels. Hope it was as exciting for you as it was for me!

Remember, keeping these essential points in mind will go a long way in ensuring smooth operations – longer lifespan, improved product quality, and cost savings. Cleaning those screws and barrels is not just another boring chore, it’s a necessity!

So, go ahead, don’t procrastinate, and start implementing these cleaning methods. Your plastic creations will thank you for it! Keep those injection moulding machines spick and span for optimal performance.

Stay tuned for more exciting adventures in the world of manufacturing and don’t forget to give your injection moulding machines the TLC they deserve!

That’s a wrap! Until next time, folks!

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Frequently Asked Questions

Daoben has the SOP (Standard Operation Procedure) and all the production steps must follow up this SOP. Every machine needs at least automatic running over 72 hours and must be inspected carefully before shipment.

Actually, the delivery time of the machines is depended on the machine options. Normally, the delivery time of a standard machine could be within 1-2 months.

12 months warranty after shipment for mechanical parts, hydraulic parts, and electric components excluding the screw and barrel 6 months (not including use for recycled material or reclaimed material).

Yes, Daoben will provide one set of standard spare parts to the customer including a heater, filter, screw head, screw washer, checking ring, sealings, etc.

Surely, we have experienced technical engineers for oversea service, they would help you install machines and support training to workers also. Currently, we provide visits online by video call for COVID-19.

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