Volumetric dispensing brings new levels of repeatability to medical device manufacturing, explains Claude Bergeron
As medical device companies look to reduce rework and improve accuracy, repeatability has become an important requirement when purchasing manufacturing equipment. This helps get parts inspected and approved in a timelier manner.
A recent project saw application requirements that included: ability to inject fluid into a small diameter hole on the plunger stop component; apply consistent amount of fluid at a weight of less than 0.2mL; repeatable dispensing with accuracy of ± 1%; and remote dispensing control through a PLC.
Previous Process
Before purchasing the 797PCP-2K progressive cavity pump, the epoxy was applied in two places on the plunger stop component using a two-component fluid dispensing machine. The machine was fed through a drum and into a syringe, which would dispense onto the part.
Drawing the fluid from the drum left too much time for the material to sit, and the fluid would quickly cure before the material dispensed. This left a large amount of material unusable, which led to costly waste. The team went back to manual dispensing, which slowed their process tremendously.
Results
When the team reached out to EFD for help, they made it clear that achieving repeatability was their most important goal. Based on this need and their two-part fluid, the 797PCP-2K progressive cavity pump was recommended. This innovative volumetric dispensing system is highly repeatable, with fluid deposit accuracy of ±1%, which met the accuracy requirements exactly.
Nordson EFD’s 797PCP-2K series pumps precisely meter accurate ratios of part A and part B materials through static mixers for highly repeatable dispensing with fluid deposit accuracy at +/-1%.
The 7197PCP-DIN-NX controller was introduced to the team when they mentioned they were looking for a way to control their dispensing through a PLC. This network capable controller provides precise control of dispensing parameters for automated dispensing applications. It allows direct communication with a PLC or other manufacturing plant controllers using NX protocol via Ethernet for Smart Factory integration.
The network-capable controller allows direct communication with a programmable logic controller (PLC) or other manufacturing plant controllers using NX protocol over transmission control protocol/internet protocol (TCP/IP) via Ethernet.
The ProPlus automated dispensing system was something that the team had previously purchased and already had in-house. The level of precision required for this plunger stop application could only be achieved on a highly repeatable, closed-loop dispensing system equipped with a CCD camera and
a tip detect device, all of which the ProPlus offers.
As the system includes specialised DispenseMotion software with a fully integrated CCD smart vision camera and three types of feedback – contact, optical, and non-contact laser height sensing – it ensures absolute accurate fluid placement, even over rough or uneven surfaces.
With the 20ga SmoothFlow tapered tip attached to a Series 190 spiral bayonet mixer, and the 797PCP-2K on a ProPlus robot, the team was able to achieve the highest repeatability and most precise fluid deposits for their application.
After implementing all the Nordson EFD fluid dispensing equipment that was recommended, the team realised they had found the dispensing process they had been looking for. The 797PCP-2K dispensed the exact amount of fluid each time to reduce waste and cost. The fluid was no longer sitting long enough to start curing, like in the previous process, and the deposits were the correct weight and size that was needed. The small gauge dispensing tip allowed the deposits to be accurately measured and placed neatly on the plunger stop component.
This new method of dispensing has helped the team tremendously and they are planning to purchase more EFD equipment in the future.
Claude Bergeron is with Nordson EFD
