Purge compounds for extrusion have a lower MFI compared to those used in injection molding. Injection molding purge compounds should be able to clean hot runner gates.
Frequently Asked Questions
Thermoplastic processing is done in many different ways with many different polymers at a wide range of temperatures. Universal purging compounds are available on the market, however they are extremely compromised offerings that are less effective than purging compounds developed for specific polymers, temperatures and process settings.
Various factors like temperature and application time can have an influence on the cleaning result and need to be taken into consideration when selecting and utilizing a purging compound.
Not all purging compounds are safe for use in hot runner systems; however there are some purging compounds which were developed to be hot runner safe. The specifications of the manufacturer of the hot runner system should also be noted.
There are two major classes of purging compounds in the market. One is referred to as mechanical or abrasive purging compounds – these are compounds where the cleaning process is based on the mechanical action of hard particles, e.g. glass. The other type of purging compounds are chemical purging compounds – with these the cleaning process relies on chemical additives that initiate some form of chemical reaction. Hybrid type purging compounds combine elements of both mechanical and chemical actions. Purging compounds can come in a ready-to-use format where the product can be used directly from the container or in a concentrate format which requires mixing before use.
A well-selected purging compound that matches with your process and polymer can provide extensive production benefits such as: time savings (shorter color and material change-over times), material savings, fewer rejects, lower scrap, higher productivity and quality, positive long-term effects on machine cleaning and less wear and tear on machine components.
A lot of different polymers are used in thermoplastic processing. The color change operation can be a time and material intensive process, especially in situations where hot runner manifolds are involved. A purge compound specialized for the operating parameters and materials being processed can help to tremendously reduce the amount of time and material required to clean the machine. Specific purge compounds provide maximum performance. Optimal change-over performance can only be achieved with the right purging compound as different polymers are not compatible to each other
The amount of Ultra Purge™ needed is the capacity of one barrel. To achieve one barrel capacity, load Ultra Purge™ into the machine until you see it being ejected from the machine.
No, Ultra Purge™ does not leave behind any residue because it does not stick to any metal surfaces.
Most grades of Ultra Purge™ are designed to clean hot runners. We have two different procedures for purging hot runners, with mold open and with mold closed. Watch some of our videos to learn more.
Ultra Purge™ is effective at purging all thermoplastic resins in injection molding, extrusion, blown film and blow molding applications.
Yes, Ultra Purge™ is efficient at removing carbon build up from the screw and hot runners. When the carbon deposit is excessive, we recommend manually cleaning the screw and then using Ultra Purge™ in a preventative maintenance fashion to prevent the formation of carbon.
All grades of Ultra Purge™ have a corresponding concentrated (Pure) grade. Please note that concentrated (Pure) grades must be mixed with a recommended carrier.
The addition of purge compound into the regrind stream for part production is not recommended as it will affect the physical properties of the final part, likely resulting in rejected parts.
A purge compound that is contaminated with color, black specks or dissimilar materials has already been saturated or partially saturated with contaminants and will not exhibit the potency of virgin purge compound. Therefore, it should not be reused as it will not produce an efficient purge.
All grades of Ultra Purge™ are moldable and can be safely injected in the mold. It is possible with certain applications that by molding Ultra Purge™, you will obtain a short shot. This is due to the fact that the melt index of Ultra Purge™ may be slightly different from the resin that you were previously molding. If molding a short shot is a problem please contact our technical support team.
Ultra Purge™ 1001 and Ultra Purge™ BP are recommended grades to clean hot runners in stack mold applications with no valve gated hot runners. Ultra Purge™ BP is a concentrated (pure) grade that needs to be mixed with your current production resin.
No. In the past, chemical purging compounds were associated with noxious odors. The revolutionary technology in Ultra Purge™ allows it to achieve a thorough cleaning, typically associated with chemical purging compounds, without releasing any noxious fumes/odors. Ultra Purge™ can be safely used in clean and white rooms.
Ultra Purge™ grades are purely chemical purging compounds, or hybrid type, and in order to complete their reaction a 3 to 5 minute soak time is required. However, allowing Ultra Purge™ to soak more than 5 minutes will not enhance its performance.
We recommend reducing the shot size to 10% of the maximum allowed shot size while purging with Ultra Purge™. This guarantees a more thorough cleaning of the check ring valve.
Both procedures can be used to clean the hot runners and there isn’t really one procedure that is better than the other one. Best results really depend on your application. Please consult with our qualified technical staff because in cases of purging with a closed mold short shorts may occur.
It is very difficult to state the specific time that will be required for Ultra Purge™ to fully clean a machine. There are too many variables, such as machine type, mechanical condition and type of resin that influence the cleaning process. However, the time required will be notably less than the time of purging with virgin resin.
According to our studies, and the results observed by many of our customers, using Ultra Purge™ helps reduce downtime up to 80% and reduce scrap up to 85%.
Ultra Purge™ grades are mainly chemical purging compounds, with some hybrid grades, and all come in pellet form. Most Ultra Purge™ grades look like a “salt and pepper” blend because of the active ingredient and the carrier.
ULTRA-X™ is a proprietary technology that is added to certain Ultra Purge™ grades to enhance the performance, thus making it more efficient and user friendly.
From internal studies, and controlled tests performed with selected customers, the new ULTRA-X™ technology has shown an increased cleaning power of roughly 30% compared to previous grades of Ultra Purge™ designed for the same application. ULTRA-X™ technology is applied to Ultra Purge™ grades designed to clean crystalline and amorphous plastic resins. In addition to color changes, the new ULTRA-X™ technology has shown a great improvement in the removal of carbon deposits.
At present, we have introduced ULTRA-X™ technology in two Ultra Purge™ product families, Ultra Purge™ 5150 family and Ultra Purge™ 5160 family. The Ultra Purge™ 5150 family is designed to purge crystalline resins while the Ultra Purge™ 5160 family is designed to purge amorphous resins.