CR Onsrud Routed a Porsche 917k from a Precision Board Bonded Block

CR Onsrud wanted to show off their 5-axis Qube CNC machine at trade shows, so they got in touch with Coastal Enterprises to throw some ideas around.  Onsrud regularly uses Precision Board as demo material on their routers, but they wanted to really highlight the capabilities of the Qube for high-speed machining and trimming of advanced materials used for aerospace, automotive, marine, defense and pattern shops.  They decided they would fabricate a prototype of the Porsche 917k out of a custom-bonded Precision Board block live at IMTS 2018.  This is how they did it.

porsche 917k

While CR Onsrud sent a detailed drawing to Coastal Enterprises that laid out what the dimensions of the custom-bonded block would need to be, customers can submit anything from a rough sketch with dimensions all the way up to a detailed drawing.  We’ll design a custom bonded step-tool from that sketch or drawing, saving you material costs and routing time.

In order for Onsrud to machine the Porsche 917k shape out of the Precision Board, it would need to be 74″ x 34″ x 18″ and fabricated from PBLT-15 Precision Board Tooling Board.  Coastal would create three bonded blocks; one for testing at Onsrud’s facility in North Carolina, one for the International Woodworking Fair in Atlanta and one for the International Manufacturing Technology Show in Chicago.

According to Jeff Onsrud, Director of Sales and Business Development at CR Onsrud, “we typically will do a setup where we prove out the program and then do a final test cut at our facility.”  He added, “this ensures that there are no machining defects due to bond lines, which is important to achieving a usable mold straight off the machine.”

Onsrud did the Porsche project in collaboration with Autodesk, using their Powermill software.

The PBLT-15 Precision Board pieces were bonded together using EP-76, a two-part epoxy manufactured by Coastal Enterprises.

“We add PB Granules to the EP-76 epoxy to match the density of the material when bonding pieces together” said Chuck Miller, President of Coastal Enterprises. “This allows for smooth routing straight through the material without having to take bond-lines into account.  This also helps create an almost imperceptible bond-line in the finished piece and reduces issues associated with bond-line shrinkage and print,” he added.

When bonding custom step tools in-house, Coastal Enterprises has three adhesive options to choose from depending on the application and project requirements.  In most tooling applications we use our EP-76 Epoxy adhesive, but we also offer PB Bond 240 and PB Fastset.

The three bonded blocks were shipped to CR Onsrud who took them on the road to the IWF show last August and the IMTS show last September.  They sent us the video above from the live demonstration at IMTS of machining a Porsche 917k from a Precision Board bonded block.

Jeff added, “the Precision Board block was bonded together so tightly and the densities matched so perfectly that we didn’t even notice the bond lines when machining the material.”

CR Onsrud used their Qube CNC to rout the Precision Board with the following speeds and feeds settings:

  • Total cycle time was around 16 hours
  • Roughing feed rates were 500 inches per minute (IPM)
  • Finishing feed rates were 400 inches per minute (IPM)

And here’s another look at that Porsche 917k prototype being routed by CR Onsrud.

Of course, the fine folks at CR Onsrud had a little fun with this project, posting updates to their Instagram account throughout the process.  Our favorite is the “pretending to drive the car” photo.

The QUBE from C.R. Onsrud was developed for companies seeking 5-axis high-speed trimming and machining of advanced materials used in the aerospace, automotive, defense, marine, and pattern shop industries. This enclosed solution gives users a large work volume for machining molds, prototypes, and complex composite or thermoformed plastic parts while containing debris and isolating the operator from the machining zone and airborne particles. The machine design allows for various methods of work holding such as mechanical hold down and vacuum. Accommodation for oversized parts is achieved via removable side panels.

C.R. Onsrud, Inc. is located in Troutman, NC and specializes in 3-Axis and 5-Axis CNC Machining Centers, CNC Routers, CNC Mills, and Inverted Routers, primarily for the Composite Machining, Aerospace Industries, Plastics Routing, Hard Wood Routing, Panel Processing, Solidwood Routing, Aluminum Milling, Steel Milling, FRP machining, Composite Mold Making, Alloy Milling, Superalloy Machining, Carbon Fiber Machining, Carbon Graphite Machining, Door, Stair, Window, and Custom Millwork.

With its roots in Aerospace, Precision Board High-Density Urethane Tooling Board is specifically engineered to meet the demands of a broad range of tooling and tool making applications. Both PBLT Tooling Board (<200º F) and PBHT Tooling Board (<300º F), possess excellent machining characteristics and dimensional stability for tool making. Precision Board HDU Tooling Board is ideal for soft tooling and rapid prototyping because it can be more rapidly machined and it is more economical than alloy or epoxy-based alternatives.

Ask about our custom-bonded blocks, fast turnaround time, and sign up for our weekly e-blasts, including the monthly Tooling Tidbit (bite-size bits of info on using Precision Board).

Introducing newly updated Precision Board Plus

Staying relevant in the modern composites industry requires a delicate balancing act of honest trial and error. In order to grow and mature, a manufacturer must identify the areas in which a product or process can be improved. This requires transparency and self-awareness; the will to acknowledge one’s own shortcomings and confront them in the open. We here at Coastal Enterprises believe that that no progress can be made without serious self-reflection, and we constantly strive to reinvent, to refine, and to reevaluate ourselves in the midst of changing times and shifting standards. With this in mind, we are proud to introduce a newly updated process for Precision Board Plus, a testament to our continuing commitment to adaptable excellence.

close up New mat

The processing changes we have made to Precision Board are based around our own careful study of industry trends and requirements, in order to more closely suit the needs of our customers. The new Precision Board features a tighter cell structure, providing a smoother surface finish and increased strength profile. No matter what the application, from low-weight signage and display construction to autoclave-cured tooling, stronger is always better. Whether it’s an exterior sign that needs to survive a harsh winter or a vacuum form/layup tool subjected to extreme temperatures, Precision Board has the durability you need for your specific project.


Another important benefit of our stronger, tighter, redesigned cell wall structure is the sharper edge machining we’ve achieved with Precision Board. It’s now much easier to dial in CNC speeds and feeds to control the router bit, to determine the amount of chips and dust produced while machining. Check out the short video above showing Precision Board being machined, producing mostly chips and little to no dust. Speeds and feeds were selected from the Onsrud router bit guide for machining Precision Board. Check out machining settings for all Precision Board densities to optimize your chip load. 


All fifteen standard densities of our new Precision Board have a higher durometer, as well as increased compression and tensile strength across the board. We have standard densities ranging from 4pcf to 75pcf in both our PBLT (200°) and PBHT (300°) materials, with sheet sizes from 20”x60” to 5’x10’ and thicknesses from ¼” to 24”. With such a wide variety of densities, sheet sizes, and temperature tolerances, Precision Board can easily be adapted to most projects. But please, don’t take our word for it. Get your free sample today, and see for yourself how our new Precision Board can work for you!

photo 1

Did you know: Coastal Enterprises constructs custom Precision Board mandrels to order? With the updated production process for our material, the quality and adaptability of our mandrels are top notch. Check out our recent blog post to find out how to streamline your filament winding process.

Ten Tips For Working With Precision Board Plus HDU

1. Carbide cutters are not mandatory when cutting Precision Board Plus. Because it is non-abrasive, Precision Board Plus can be cut with anything that cuts wood, but much easier.


2. To maximize CNC efficiency and cutting time, and to minimize dust and increase chips, the Onsrud Router Bit Selector Guide provides guidelines for proper router bits, speeds and feeds.

3. After you have primed Precision Board Plus using FSC-88WB Primer/Filler, it is best to dry using a large shop fan. Do not place in the sun, as this will cause it to dry too fast resulting in blisters. The FSC-88WB Primer/Filler training video can be seen here.


4. Be sure to prime and paint all sides of your Precision Board Plus sign. Because it does not have grain, it has no beam strength and can be pulled in the direction of the drying paint.


5. When sandblasting Precision Board Plus, use a larger grit for larger texture. Similarly, a finer grit allows for finer texture. Aluminum oxide is used most often.


6. If something happens to your sign during the build process, it is possible to fix the damaged surface. FSC-360WB Crack Filling & Repair Putty dries quickly and sands easily, and can really save the day in the event of a mistake.


7. Optimize your Precision Board Plus purchase by bonding and laminating the excess using PB Fast Set or PB Bond-240 adhesive.


8. PB Resin can provide an eye-catching, ultra-smooth protective finish to your sign. Be sure to only add enough lettering enamel to the clear PB Resin that will hide text on a printed page.

9. If you do not have time to route in wood grain, or to sandblast, TSF-45 or PB Hardcoat are excellent time saving alternatives for simulating wood grain. Apply both directly to raw Precision Board Plus, eliminating the priming step.


10. If you have a question, call us! We offer free technical support and are happy to assist in any way we can.

Router Bit Search Guide – Improve your RPM and Feed Rates

Have you ever been not completely sure which router bit would work best for the Precision Board Plus you were about to cut?

Well worry no more, LMT Onsrud, the experts in plastic routing have a router bit search tool to help you select the proper bit. Using the correct router bit will allow you to maintain the best RPM and feed rates possible, decreasing cutting time and maximizing machining production.

Check out this video of a Zund router cutting Precision Board Plus PBLT-30 very quickly:


Speeds and Feeds

One of the more frequent inquiries we receive at Coastal Enterprises involves questions about machining Precision Board Plus HDU. For those that are experienced in working with the product, we typically hear things like, “this stuff cuts like butter” ,“my cutters last longer”, “I can set my CNC to a higher feed rate” or our favorite, “I get more chips and less dust”. Of course we remind these customers that these performance factors are the result of Precision Board Plus HDU being a non-abrasive cellular product that has no grain.

But if you’ve never used the product, you may want to know “what type of cutter works best” and “where do I start with my speed and feed settings”? First of all, a wide variety of HSS cutters commonly used for wood and plastics work very well for machining Precision Board Plus HDU, and a wide range of settings will produce great results.


Initial Setup

As a starting point, consider the testing done by cutter manufacturer Onsrud on various densities of Precision Board Plus HDU. Using a carbide double-edge upcut spiral 0.125” cutter with PBLT-18 (18lb. density), best results were achieved with an RPM of 14,000, a feed rate of 200 IPM, at a depth of 1” per pass. Similarly good results were achieved using a carbide double-edge upcut 0.25” cutter spinning at 18,000 RPM, with a feed rate of 75 IPM at a depth of 1.5” per pass. Both settings produced a smooth surface finish.

Keep in mind that while this data was generated with carbide cutters, HSS cutters also perform very well due to the non-abrasive nature of Precision Board Plus HDU. Adam Prentiss of Lormac Plastics has extensive experience machining Precision Board Plus HDU, particularly PBLT-30 and  PBLT-40. He finds dialing in the right speed and feed very easy with both HSS and carbide cutters.

Here are settings used by Onsrud that produced the best results across a range of Precision Board Plus densities. These and other data for machine settings for a variety of materials can be found at

Typical Precision Board Plus CNC Settings


Chip Load

Remember it’s always a good idea to optimize your chip load by setting your feed rate and cutter speed to yield the largest chip that produces the desired surface finish. While Precision Board Plus HDU does not conduct heat and is non-abrasive, this will ensure that heat is carried away from the cutter, prolonging tool life. Onsrud reminds us of this useful formula:

Chip Load = Feed rate/ RPM x # of flutes

To increase chip load: 

  • Increase feed rate
  • Decrease RPM
  • Use a cutter with fewer flutes

To decrease chip load: 

  • Decrease feed rate
  • Increase RPM
  • Use a cutter with more flutes

With a little experimentation you’ll become an expert at machining Precision Board Plus in no time. Proper cutter selection and machine setup will produce a smooth cut, leaving chips that fall to the ground and do not become airborne. And because we’ve added an anti-static agent to Precision Board Plus, chips will not cling to your work or your equipment.

Did You Know?

Precision Board Plus Precision Board Plus does not out-gas during the autoclave curing process, so it’s ideal for prepreg layup tools and mold patterns (see autoclave ramping procedures). To learn more about the capabilities of Precision Board Plus, view or download our product data sheets.

Need help with a quote? Click here or call us at 800-845-0745