Placentia, California – Kipe Moulds Inc. of Placentia, California, has improved its micro injection system for moulding small liquid silicone rubber parts.
Kipe Moulds President George Kipe, a serial inventor, began developing the MD system in 2007 for the Jacksonville, Florida-based Vistakon division of Johnson & Johnson Vision Care Inc. Vistakon manufactures ophthalmic devices.
Vistakon was issued US patent 8,721,322 in November 2011 and listed Kipe among the inventors. Years of development work had led Kipe to understand the mechanics and requirements for a robust silicone micro moulding platform.
“For really small parts, it is necessary to have a very small injection unit,” said Dana King, business development director for Kipe Moulds. “If a system can repeatedly direct inject a part that is only 0.010 grams, you have a very capable system. Our system does just that.”
A licensing agreement with Vistakon allows Kipe Moulds to sell the technology for any industry.
“We truly believe this is the best micro system for LSR on the market,” King said.
In early 2013, Kipe Moulds began supplying the technology to Vernay Laboratories Inc. for production at its Griffin, Ga., manufacturing facility. Vernay makes parts for flow control of fluids or gases in multiple applications for medical, automotive and commercial markets.
“It’s fabulous” for flash-free moulding of LSR parts, said Paul Grund, Vernay’s global leader for liquid injection moulding technology.
Another unidentified Kipe Moulds customer has worked with the MD system on difficult small parts for several months.
During 2015, Kipe Moulds linked with its micro injection unit supplier, Sadaplast America Inc., to add a servo system to the plunger. Sadaplast of Campobello, S.C., is a servo integration and programming developer.
For trials in August, Sadaplast installed the servo-actuated microdeck system on a compact Boy XS injection moulding machine.
In the new configuration, the MD line incorporates a servo-actuated micro plunger with fully controllable injection parameters. The system monitors and records starting injection pressure in the plunger system.
“It is exciting to go to servo from pneumatic,” King said.
The MD line includes a pressure transducer positioned directly adjacent to the system’s valve gate nozzle “to generate the most accurate picture of injection pressures possible,” King said, noting that conventional machines measure pressure via hydraulics or load cells far removed from the action.
A graphic interface shows the shape of the pressure curve providing, King said, “a truer picture of the injection process.”
Kipe Moulds demonstrated the earlier technology on a Boy machine at NPE 2015 in March in Orlando, Florida. The mould ran a trial 0.009-gram micro-septum.
Next, Kipe Moulds will operate an MD unit with the servo system during the 3-5 Nov Medical Design & Manufacturing show in Minneapolis. The unit will make a septum part that is direct injected and has a weight of 0.007 grams.
To our knowledge, no other machine manufacturer can claim to have a system capable of producing such a small shot with no waste,” King said.
For interfacing with the mould, Kipe Moulds’ standard valve gate tip options are used along with the basic 0.5-inch spherical radius. “Our servo controlled system can act as a standalone barrel for second shot applications on two-shot moulds,” King said.
Kipe Moulds believes its understanding of the material and process at a small scale and use of the precise micro injection unit can provide “the best results” to a processor, King said. “We seek to understand and discuss strategies for the entire process from material management to handling, inspection and processing.”
He said the processor’s alternative is to run a mould with a large number of cavities and a large cold runner in order to get the shot weight into a reasonable size for standard moulding machine technology.
“The resulting yields tend to be low and involve sorting by hand under a microscope — very labor intensive and subjective,” he noted. “If the same inspector looks at parts from our microdeck with a 95 percent yield and a large mould with a 50 percent yield, that inspector is spending nearly twice as long per good part to qualify parts,” King said.
For nano-moulding LSR, the MD 125 model can directly inject parts from 0.003 grams to about 1.0 grams. Several larger-size models have weight capacities up to 8 grams.
Kipe Moulds employs about 25, occupies 14,000 square feet and has annual sales of about $3.5 million (€3.1 million). “We have seen our sales double in the past two years,” King said. During 2016, “we expect to grow 20-30 percent.”
Kipe Moulds was among the first cold runner manufacturers in the US and has that product line as a core business. “We are able to support some customers with lead times of just three weeks,” King said.
Liquid silicone mould making is also a core business for Kipe Moulds.
“We hope the micro injection unit will grow into another solid segment of our business,” King said.