Heat Tech Systems Inc. and Complete Plastics Systems Inc. have been in the industry for many years and through they have gained invaluable experience in the molding industry. Injection molding barrels and the screws that go with them are the heart of the press. In injection molding there is more wear and tear on these components because of its cycle than the rest of the machine. It is more important to make sure that you get the correct combination of materials between the screw and the barrel to ensure the longest life as well as being able to run as fast and effective as possible.
With the fast paced cycles, RPMs, and back pressures that certain process engineers can run, premature wear on the cylinder walls of an injection molding barrel can become one of the biggest reasons inconsistent shots or the inability to hold cushion to occur. In a vast amount of instances we have been able to save the customer money by just measuring the stroke end of the barrel and know that the wear is becoming excessive. Certain poorly manufactured barrels will cause the barrels to wear in almost a watermelon shape in either the transition or metering ends causing uneven wear and certain times can prevent the ability to reline an injection molding barrel. Certain overseas bimetallic barrels will wear almost as fast as the screw. When we work with our customers we always try to make sure that you get twice the life of the barrel in comparison to the screw.
With our team of maintenance and manufacturing personnel we have the knowledge and understanding to ensure that you will get the maximum life expectancy and that we will also be able to reline your barrels. We will work with you and go over prints and any processing ideas you may have. We supply full steel barrels in most cases because the bi-metal blanks coming from over seas can ware and have issue when rebuilding for the next long life of your production.
Barrels are normally made in four materials. Nitralloy nitride, D2, CPM 10V and Carbide. These materials handle just about any resins that can be used in the plastics industry. Nitralloy Nitride is the most common because it is used on all General Purpose application and normally comes standard on all OEM machines. The Nitalloy is very good on any mild material application without fillers or corrosives.
Barrels made from D2 are also very good for any application but also allows a better protection from pitting caused by PVC or Poly Carbonate. The D2 material will stop the black specking caused by resin sticking that can come from a Nitrided barrel.
CPM 10V like the screw material works very well in higher wear applications such as glassed filled, talc filled or fire retardant materials. The CPM material will give about twice the life of the barrel against the Nitralloy barrel.
Carbide Barrels will again last twice as long as the CPM barrel but at a much higher cost & delivery time. But if you are running 50% Glass filled material and really need the wear protection the carbide is a very good option.
There are spun cast barrels on the market brought in from China and India that you should be very careful of. We have several sitting in our shop that have cracked & or broken in half. They are less money but if they last 6 months and crack or break the 20% you saved will not come close to the cost of buying a new barrel. Always ask if you are getting a spun cast barrel before you buy. You will be happy you did.