Product Design and Manufacturing


Introducing Mike Hilgendorf

Manufacturing Engineer / Product Designer including part & mold design of automotive, medical, electro-mechanical and fuel cell parts.

Process experience includes: injection molding (including sample start-ups), roto-molding, metal fabrication, plastic welding and fabrication.

Skills include: SolidWorks, Master Cam, AutoCAD, Agile, PDM Works, Injection mold making, mold repair, molding technician trainer.

Training includes: RJG Decoupled Molding, part & mold cost estimating, Lean manufacturing, DFMA, FMEA, BOM creation.


Plastics Part & Mold Design

Mike is an expert in all aspects of plastics manufacturing from part design to mold design to processing and cell assembly. Injection molding is his forte` and he has worked for some of the largest molders in the world. Mike has relationships with several key manufacturers in the USA and Asia. Doing it right the first time makes all the difference! Mike can make sure you get the right designs and quality molds at great prices which can make a huge difference in getting your project completed within budget. Let his experience help you make the right decisions.

Rotational molding is another area of Mike's expertise. Often referred to as roto-molding, the process offers low cost molds for large hollow shaped parts such as tanks, floats, enclosures and cases. Many sheet metal products can be redesigned using roto-molding allowing threaded inserts and metal parts to be molded right into the part. This can save costly secondary assembly operations while avoiding less reliable bonding or sealing operations. Ask if your product is a fit for roto-molding.

Mike offers contract designing services with over 15 years of experience bringing products to life. Whether you need a concept design modeled in 3D or drawings for manufacturing, he can help. Products can be made from plastics, sheet metal, structural steel and more. Clients and employers have found Mike to be skilled in creating cost effective, robust designs, mindful of easy assembly and serviceability.

Some examples can be seen below;


Case study #1

A fuel cell company needed a plastic part with features that had never been done before via injection molding. Several companies turned them away saying it was not feasible when Mike was asked to take a look. The Noryl part was very thin (.025”) and long, which was a challenge in itself, but they also needed a screen area in the part consisting of 1320 holes spaced .012” apart in a specified area. Holes needed to be .009 to .011” in diameter. See the photo below of an actual molded part. Mike built the mold and ran the parts on the clients own molding machine purchased for this challenge.


The challenge of filling a thin part was accomplished with a muti-gating design. Mike devised this design without the aid of “Mold Flow” relying on his experience instead of expensive software. Small “Viper” gates were created to develop material shear as it passed through them, keeping the plastic molten longer.

The screen (a field of 1320 holes) was a little more challenging and took some creative thinking as it is impossible to flow Noryl the distance needed through the string-like cross sections of the screen. An insert was created in the mold with 1320 cone shaped pins tapering from .013 at the base to .008” at the tip. They were produced by a staight drilled electrode using an orbital edm process that swept farther around as it raised up on the pins. The delicate pins could not shut off for fear of smashing the tiny ends so the pin field area was made thicker than the rest of the part. The conical pins also protruded higher than the rest of the part but short of shutting off against the top of the mold. Rather than having to flow plastic through the strings to fill the screen area, this thickened area over the pins allowed plastic to flow above the field and down between each pin with ease.

A secondary planing operation was then used to cut the thick area down to the thickness of the rest of the part exposing the field of tiny holes. Prior to this, parts were being produced by machining plate stock to the desired thickness and circuit board drilling the screen field. The machining process cost $64 per piece, but with Mike’s mold parts were produced for < $1.

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Case study #2

A Fuel Cell company needed a manifold injection molded with internal curved channels like the machined prototype pictured below. Zinc suspended in fluid was passed through the manifold and delivered to each cell. To make the prototype they machined two pieces and glued them together. Glue oozes into the channels and along with gaps would trap zinc which eventually built up and caused a blockage. Molding a one-piece part would be much more desireable but very challenging. Mike was asked to take on this challenge and he accepted.

Mike decided that “Lost Core” molding would be the best possible approach. This process uses a technology that involves inserting a core (generally of cast metal) into an injection mold, overmolding it with a thermoset A polymer-based liquid or powder that becomes solid when heated, placed under pressure, treated with a chemical or via radiation. The curing process creates a chemical bond that, unlike a thermoplastic, prevents the material from being remelted. See thermoplastic.  or engineering thermoplasticA polymer material that turns to liquid when heated and becomes solid when cooled. There are more than 40 types of thermoplastics, including acrylic, polypropylene, polycarbonate and polyethylene.
..... Click the link for more information. material, and then melting or washing the core out of the part. PEEK was chosen as the housing material and a eutectic core of tin / bismuth was identified with a low enough melting point below that of PEEK. The resulting part is pictured along with the prototype below. For more on lost core molding follow this link:

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Case study #3

A San Diego Company needed a quick turn around on 3 parts of a speaker assembly. Concept designs existed that were not injection moldable. A moldable design and 100 parts were needed for a trade show in 4 weeks. Mike took the designs and made the needed design changes in 4 days. Molds were designed by China sources in 3 days under Mike’s direct oversight and molds were completed in 2 weeks. 100 pieces of 3 different parts were received in time for the show… ANOTHER HAPPY CUSTOMER ! See part photos & mold dwg below.

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