Kipe Molds Inc. of Placentia, Calif., has improved its micro injection system for molding small liquid silicone rubber parts.
Kipe Molds President George Kipe, a serial inventor, began developing the MD system in 2007 for the Jacksonville, Fla.-based Vistakon division of Johnson & Johnson Vision Care Inc. Vistakon manufactures ophthalmic devices.
Vistakon was issued U.S. 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 molding platform.
“For really small parts, it is necessary to have a very small injection unit,” said Dana King, business development director for Kipe Molds. “If a system can repeatably 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 Molds 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 Molds 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 molding of LSR parts, said Paul Grund, Vernay's global leader for liquid injection molding technology.
Another unidentified Kipe Molds customer has worked with the MD system on difficult small parts for several months.
During 2015, Kipe Molds 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 molding 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 Molds demonstrated the earlier technology on a Boy machine at NPE 2015 in March in Orlando, Fla. The mold ran a trial 0.009-gram micro-septum.
Next, Kipe Molds will operate an MD unit with the servo system during the Nov. 3-5 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 mold, Kipe Molds' 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 molds,” King said.
Kipe Molds 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 mold with a large number of cavities and a large cold runner in order to get the shot weight into a reasonable size for standard molding 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 mold with a 50 percent yield, that inspector is spending nearly twice as long per good part to qualify parts,” King said.
For nano-molding 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 Molds employs about 25, occupies 14,000 square feet and has annual sales of about $3.5 million. “We have seen our sales double in the past two years,” King said. During 2016, “we expect to grow 20-30 percent.”
Kipe Molds was among the first cold runner manufacturers in the U.S. 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 mold making is also a core business for Kipe Molds.
“We hope the micro injection unit will grow into another solid segment of our business,” King said.