Optimizing the LSR Production Process
Optimizing the LSR Production Process
To achieve LSR’s myriad benefits for such a wide variety of applications, LSR injection molding machines must be optimized to provide the greatest value and ease of use.
While LSR equipment is similar in many ways to the plastics industry, many plastic tool makers try to manufacture LSR tools in the same manner as a plastic tool, which can lead to manufacturing failures. It is essential to use tool makers with a specific track record making LSR tooling. Also critical is working with an injection molding machine company that can assist with processing challenges, since successful LSR manufacturing requires that all components work properly together.
The most common pain points in LSR manufacturing are managing waste and controlling color changes and additives. Excess material is wasted because it is difficult to reclaim it due to such issues as air bubbles, loss of certification, and a lack of lot tracking. Color changes can pose production down time, because extensive cleaning processes between colors can take as long as four to six hours. In addition, control of color or additives is also a concern, especially controlling functional additives in the medical device industry.
Both waste and increased additive control can be addressed through new closed-loop control system technology being developed. For example, the Graco Fluid Automation F4 series systems use a dosing valve and a high-resolution flow meter to provide a closed-loop control for third and fourth stream additives, such as color and medications. The system monitors and adjusts to ensure the additive is being dispensed in the appropriate amount. If there is an out of tolerance condition, the system stops production to prevent manufacturing bad parts.
In addition, controlling the flow of the two primary material components in a closed-loop system allows the machine to react to changes in the material viscosity and the presence of air bubbles. Operators can vary the ratio to ensure the correct amount of material is used.
The closed loop control of the two-component LSR’s dispense ratio is achieved by monitoring the material flow using high-resolution, helical gear-style flow meters. The helical gear uses multiple gear teeth to measure the flow in very small increments. Information from these flow meters is fed back to the controller, which operates the valve to alter the flow of material to the flow meter, forming the closed loop.
The increased number of measurements provides more assurance that the machine is running on-ratio to prevent manufacturing of bad parts. Closed loop control therefore significantly reduces waste and rework caused by off-ratio dispensing.
The new system offers a simple calibration routine that can be performed by the end user as necessary for a particular process. This can have a significant impact on product quality. The sample is collected and weighed, and the resulting data is entered into the advanced display module to calculate the current actual dispense ratio and calibrate the control system.
A variety of other controls help to monitor processes, which is important to reliably manage the LSR system for its entire lifetime. An example is the GCA (Graco Control Architecture), which provides longer life cycles than standard PLC products, and has a much faster response time than other control architecture types.
Overall, the new technology helps manufacturers reduce waste, ensure proper additive introduction, and control the operation of LSR dispense systems, leading to hassle-free production.
LSR at the Leading Edge
The LSR industry is in a state of rapid expansion, and continues to offer new and improved materials to replace older technologies with longer-lasting, more effective solutions. Improvements to LSR physical properties for individual applications means LSR will likely continue replacing traditional rubber materials in existing industries – and probably move into others. With the advanced LSR dispense and production technology currently on the market, the manufacturing of LSR products can be managed to minimize issues and take full advantage of this material’s wide-ranging potential.