# Help with MDF board to use as spoil board



## KWind (Feb 21, 2014)

Looking for information on what is being used by professionals for the spoil board on the CNC. We just acquired the CNC Router and had training. We were told to purchase a Medium Density Fiberboard (30-40 lb) 5 x 10 sheet to use for the spoil board. I am posting this for the guys in the plant. We have tried different densities, moisture resistant and non, but have not had success with them. One was too light weight and the machine kept giving errors, the moisture mdf works if they scrape away some layers. Any suggestions please?


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## old55 (Aug 11, 2013)

Welcome to the forum Kevin.


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## 4DThinker (Feb 16, 2014)

On our multicam with a vacuum table we use meduim grade MDF. The bottom gets skim cut, the sheet turned over, then the top gets skim cut. From that point on the vacuum will pull through the MDF and hold down almost anything. Sheet goods 99% of the time. Hard wood depends on how twisty the board is. We'll use brass screws and screw a corner or two into the MDF if we need to. Fix minor gouges into the MDF with water putty. Re-skim it when it needs it. Usually we can run a week of 8 hour days between skims. Replace when it is too thin.


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## clarkjw16423 (Mar 19, 2014)

If you use MDF you are definitely going to want to ensure you have a table vacuum that will hold both the mdf and your work piece to the table. If you don't have a table vac you will want to ensure you have some kind of pressure foot over your spindle. I use one CNC machine for wood cutting / sheet aluminum cutting and MDF is used for that in conjunction with an outdoor table vacuum. I also use another CNC that doesn't use a table vac, but instead I designed a pressure foot that goes over the spindle to hold down boards. The material I use for this is much more stable (arboron) and moisture resistant. I needed to do this because I needed a tighter tolerance in my z-axis (to the thousandth of an inch). I use this router to route circuit boards on FR-4 material. I need to get through about .003" of copper, but not go too far into the fiberglass substrate.

Anyway, you are going to want a table vac unless you are able to either get a pressure foot or design one yourself. They are very worth it if you don't want to deal with noise / power consumption.

V/R
Jim


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## Stratton76 (Sep 4, 2012)

*CNC Spoil Board*

When using a MDF spoil board with a vacuum system ,you will have to fly cut boht faces of the sheet to get the proper air flow thru the spoil board.


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