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Infuser PRG goes to Boston at JEC Americas

News International-French

7 Nov 2012

JEC Americas 2012 - The Infuser PRG offers the state of the art in fully automated RTM Injection which puts the control of the process in the automated equipment and molds thus eliminating the reliance on the operator for the quality and repeatability of the moldings produced.

The level of RTM & LRTM process expertise and maturity has grown and so has the demand and appreciation for greater process control from the injection systems. In the past the molder often was on a bit of exploration as they dove into the closed molding processes of RTM or LRTM and thus really did not know what they needed or certainly did not want to invest in an injection system beyond a simple metermix machine until they fully understood their process needs.


Today, the tide has turned where many who started in the process a few years back are now on the path to refine and gain a competitive advantage through automated process control.


It is clear that the most costly, or the most efficient, molding operation comes down to simply being able to control the injection process. However for those who started off with a manual or semi-automatic injection system have found themselves relying on their molding staff to hold control of the process versus letting the system automation take full control.


When we consider the fact that the most expensive component in the filling of the mold is the resin, then it is clear that efficiently filling the mold is most critical. Yet, the vast majority of the molders give full control to the molding operator, who in the most part has no idea what the original budget was set for resin usage in each part. At a conservative level it is found that over 95% of the molders are wasting well over 17% of their resin. The results of this waste is found in thick molding often plagued with air voids and cracks. Not to mention the added stress on the molds due to excessive peak exothermic temperatures.


At best today, the molders are using injection systems that provide a simple stroke counter for automatic shut off and some form of pressure limits controls to presumably prevent over pressurizing the mold. While the premise is that these features aid in conserving waste the fact remains that neither is true.


When it comes to stopping when the mold is full, relying on a stroke counter and expecting the operator to re-set a number in the counter for each different mold is no way to gain conformance. It is proven that if the operator is in fact changing the number in the stroke counter they are doing so to a total volume of resin they "feel" is needed and most often far more than was budgeted for each part.


As far as pressure controlling the process, this was the direction several years ago, in fact JHM Technologies was a strong promoter of the ZIP technology, yet as the process controls continued to evolve we realized that pressure was not the correct means of forth most control it is the flow rate, then using pressure as a "upper limit" to prevent the prescribe flow rate from exceeding the pressure limits of the mold set. By focusing on pressure, far greater control is created in a repeatable mold fill. This feature can then be programmed to have multiple steps so the fill can progressively slow down as the mold is progressively filling thus never lifting the upper mold and sacrificing resin flow front control.


To add the precise amount of resin, there is no need to require the operator to set a counter or manually count pump strokes, the state of the art today is to use a RFID tag on the mold, then the operator simply places the RFID tag on the remote reader and pressing the "start" button all process control is then fully automatic.


Today the leading edge injection system provides all but not limited to the following features:

  1. Ability to teach the program, having the ability to inject once manually and the machine remember precisely how that injection was carried out and create a molding recipe automatically. That recipe can then be tweak or edited later for finer refinement. This however can only be done by a supervisor level log-in.
  2. The ability to confirm the mold cavity vacuum level is sufficient. This is one of the most common causes of scrap is improper vacuum level and often is not even realized by the molder as the root cause of their process issues.
  3. The very first drop of resin leaving the Mixhead to be a precise prescribed temperature. The machine is to recirculate the resin from the source to the Mixhead and once the resin at the Mixhead is at the prescribed temperature then open the Mixhead and begin injecting. It should also ONLY heat the resin in the heater and the hose set and NOT need to heat the whole drum.
  4. Each mold must have a preset molding recipe which is called up from memory within the machine through the instantaneous use of the RFID tag.
  5. All of the process variables, daily production logs for each molding and on-going machine maintenance logs are to be stored on a networked PC in Excel Spreadsheet format allowing for process, production and maintenance personal to retrieve this information from their desk.
  6. The catalyst ratio should be programmable and have the ability to be progressive so as to change the ratio during the fill to reduce the overall cycle time by allowing resin to cure more evenly within the mold.

At minimum the above should be a part of every injection system used in production molding of RTM and LRTM. While those that have this level of control are enjoying a tremendous competitive advantage over those who don't.


Each of the controls listed above are just the foundation features found on the Infuser PRG, which is proving to be the state of the art in high and low pressure RTM & LRTM molding worldwide today. With all this control, it is often said, that the Infuser PRG is Free in the short term when the savings are added up in the gained controls.



Booth E29