Achieving Optimal Performance When CNC Routing HDU

What are the benefits of having the correct cutting bit, and proper speed and feed settings on your CNC router?

  • Better Chip Load
  • Less Time Routing
  • More Chips, Less Dust
  • Increase The Life Of The Cutting Bit

We recently had some Precision Board Plus tested by our friends at LMT Onsrud, router bit manufacturers and expert CNC machinists, to find out the best speed and feed rates for specific densities of Precision Board Plus. The information was collected to add to the excellent router bit selector guide LMT Onsrud has, which recommends router bits as well as proper speed and feed based on selected density of Precision Board Plus. You can check this guide here.

We were additionally offered the opportunity to speak with Gary Burgus, one of LMT Onsrud’s expert Engineering Technicians (and the man who tested all the Precision Board) and walked away with some valuable information from someone who has tested hundreds, if not thousands of different materials with many CNC router bits.

All of the cutter bits Gary used were carbide tipped, but it is not necessary to use carbide with Precision Board Plus. Any HSS (high speed steel) cutting bits can also be used.

General Routing Tips for Precision Board Plus:

  • Cut in a conventional direction, Precision Board Plus cuts similar to a foam type material
  • Heavier cuts are generally better, specifically a full diameter or half diameter pass because the tool needs material to grab and cut away. Many customers who are familiar with cutting hard plastic or metal are accustomed to taking light radial cuts. Because Precision Board Plus is more similar to foam, the tools need more material to grab – be sure to leave a 50% radius.
  • Routing to depth is preferable over plunging to depth
  • Always maintain a constant chip flow
  • If you are cutting a large rectangle, or low detail shape, a 2 or 3 flute tool is your best choice. This will maintain a constant speed and feed rate.
  • If the shape you will be cutting is highly detailed, stick to a single flute tool, run it a little slower and keep a constant feed rate.

Gary also provided us with a great example:

Say you are going to cut a highly detailed sun, 20″ in diameter, and and set your CNC router to 10,000 RPM at 200″ a minute.  Because the direction will be changing so many times, a single flute tool is preferable. Even though the settings call for 200″ a minute, realistically the most you will be seeing is 60″ – 100″ a minute. Using a single flute tool will allow for the best chip load and cut.

If you are going to be cutting letters, if they are 2″ or so, a single flute tool is preferable. If the letters are 10″ – 12″ or larger, a 2 flute tool is your best bet for the ideal chip load.

Be sure to check out this excellent guide that LMT Onsrud has for selecting the proper bit (select high density urethane and proper density) at: http://www.plasticrouting.com/BitSearch.asp?Page=Material.

This video shows PBLT-30 being routed on a Zund G3 CNC router with the proper speed and feed, talk about some fast routing!

If you have any questions, we offer free technical support and can be reached at: (800) 845-0745.

Garden Railroad Magic – Rainbow Ridge Kits with Precision Board Plus!

Quickly becoming legends in the model railroad industry, Ross and Sue Piper of Rainbow Ridge Kits in Lakeside, CA have been in business for six and a half years now.

Rainbow Ridge specializes in making highly detailed, high end railroad buildings and structures.

By John and Lorrie Rockey – Glen Ellyn, Illinois

Using their ShopBot CNC router, Ross and Sue purchase Precision Board Plus HDU in 4′ x 8′ sheets, 3/4″ thick, typically densities of PBLT-15, PBLT-18 and PBLT-20, and cut them into small pieces. They then CNC patterns into them, such as wood plank, wood shingle, stone, siding and logs. They also offer custom patterns by request. The high level of detail they achieve using their ShopBot CNC Router is well known, and they recently were spotlighted by ShopBot’s website in a review you can see here.

By Dick Dale – El Cajon, CA

In addition to offering pre-cut  “Scratch Build” Precision Board Plus sheets, they also build complete structures, ready for priming and painting, and even offer completely finished (primed, painted and assembled) buildings.

By Gary Martin – Tucson, AZ

Before Ross and Sue got involved in the industry, many garden railroaders had trouble with available materials not being able to stand extreme temperatures, especially in states such as Nevada and Arizona. Previously, many garden railroad buildings were constructed out of plastic, wood or resin and were apt to become waterlogged or damaged by the sun. Precision Board Plus has proven to be the material of choice for a long-lasting model railroad structure because it will not absorb water and is unaffected by extreme temperatures (it has been tested from -425˚F to +300˚F with no degradation or breakdown).

By Andreas Walchner – Beavercreek, OH

Check out many more pictures at: http://www.rainbowridgekits.com.

Here is one of the latest offerings available through Rainbow Ridge Kits:



These pictures are from Ross and Sue’s personal garden railroad (more pictures on their website):

The Ice Cream Laboratory

Mark Blackford, owner of Signcraft in Santa Maria, CA sent us some excellent in-process pictures of a sign they made for Doc Burnstein’s Ice Cream Lab in Orcutt, CA. The sign was hand-carved from Precision Board Plus PBLT-15, except for the border which was cut on their ShopBot CNC Router. It was then painted using 1-Shot Paints. When asked why he prefers working with Precision Board Plus, Mark states: “Signcraft Santa Maria exclusively uses Precision Board Plus HDU due to its ease of carving, variety of densities, and excellent companion products such as PB Bond 240 and FSC-360WB.”

To see more of the amazing work Signcraft does, visit www.signcraftsm.com.

Thanks Mark for sending all of these great pictures!