How to Skim the MDF Sacrificial Bed on your Tekcel CNC Router: A Step-by-Step Guide

Having good, solid & secure material hold down is paramount in getting the best results when cutting any material on a flatbed CNC router.

After hours of cutting through materials and into the MDF sacrificial board, scarring and cut line tracks will be visible all over the MDF. When these are excessive, these scars can affect the vacuum hold down surface efficiency and lead to inaccurate cuts and inevitably, material movement.

…The solution? Skim the MDF surface to maintain an even and flat area and restore its optimal vacuum hold down performance again. We’ll walk you through everything you need to know about skimming the MDF bed of your Tekcel CNC router, the tools you’ll need, and a step-by-step breakdown of the process.

Why Skim the Bed of Your Tekcel CNC Router?
The high performance Vacuum table on a Tekcel CNC Router is made up of extruded aluminium slats topped with a solid PVC surface with holes & pockets drilled into them to create a vacuum seal, once covered with the MDF sacrificial surface. As mentioned, over your hours of cutting, it becomes uneven due to repeated cutting use & pressure from workpieces. When this MDF surface isn’t perfectly flat, the results can be costly with misaligned cuts, uneven engraving or expensive material movement.

Regularly skimming the bed ensures:

• Accurate depth of cut and consistent drilling & engraving depths
• Optimum tool performance & longevity
• Reduction in material movement & unnecessary wastage
• Smooth and seamless production flow
• By taking the time to maintain your MDF sacrificial surface, you’re investing in the long-term precision and productivity of your CNC router.

Tools You’ll Need to Skim your MDF sacrificial bed surface

• Tekcel CNC Router / CNC Router: Naturally, you’ll need the router itself.
• Bed Skimming Tool : This dedicated & specialised surface cutting tool bit is designed to level the surface of your MDF sacrificial board effectively. Our TBS 2434-8 35mm bed skimming tool is recommended for faster results and a smoother finish on MDF.

• New or Very Good Condition Collets: Having the correct size collet and in prime condition is key to holding any tool securely in a tool holder or spindle. Make sure you check and replace your collets regularly as this will give you far better performance. We always recommend you replace your collets every 3 months to maintain the best and safest performance. See our recommended range of collets to suit your CNC Router.

• Measuring: Tools such as digital callipers are a good idea, just to check the thickness of your sacrificial board before you start skimming, so as you have an idea of the original thickness.
• Dust Extraction System: CNC routers can generate a significant amount of dust & swarf when skimming, so it’s important to have a good, efficient dust extraction system in place to maintain a clean working environment.
• Health & Safety: Safety goggles and ear protection should always be worn while using your CNC Router.

Now that you’re equipped & ready, let’s move on to the skimming process itself.

Step-by-Step Process for Skimming the MDF Bed on Your Tekcel CNC Router

Step 1: Prepare the Router
Before starting any of the process, make sure your Tekcel CNC router is free from any material debris and that a new or existing MDF sacrificial board is the correct size and on the vacuum table straight & aligned. If using an existing board, give it a general inspection for any obvious deep cuts, debris or swarf and remove if possible.

Step 2: The Bed Skimming Tool
The next step is to load your Bed Skimming tool into the ATC Tool Holder or directly into the router’s spindle. Ensure it is properly secured and indexed or sensed using the Tool Length Sensor as standard on every Tekcel CNC Router. Loose or non-sensed tooling can cause inaccuracies during any cutting processes, especially when skimming. Always refer to the manufacturer's guidelines for proper installation of router bits.

Step 3: Set the Router’s Skim Area
With your Bed skimming tool in place, it’s time to check the sacrificial skimming file size, that is preset in the Tekcel CNC Router controller system during initial installation and training. Depending on the size of your MDF sacrificial sheet, select the correct size file and load into the system. All feeds, speeds & RPM (18,000 rpm for MDF always) are specifically preset from installation, so no need to make any changes to these. Next, enter the value or thickness you want left on your MDF sheet and confirm this. (Example: If you enter 5.5mm into the sacrificial value area and run the skim file, everything above 5.5mm will be removed by the bed skimming tool from the surface of the MDF board) Make sure that if you are using an existing sacrificial board, then the value you enter skims the board at least to the deepest cut or scar in the MDF. Please note: When using a fresh, new MDF sacrificial sheet/s, make sure you skim both sides of the MDF, to make sure the material is fully open for air to flow through freely. Once you have done this to bot sides, then you only need to skim one side moving forward when required.

Step 4: Start the Skimming Process
Once everything is set, it’s time to begin skimming. Make sure the area is clear from any other material or obstacles and run the file. As the router makes its passes, keep an eye on the process to ensure that the skimming tool is cutting evenly across the sacrificial board surface. If you notice any misses or lighter skimming, you can always pause the process and make a depth adjustment before continuing the process again. Should there be any dust debris after skimming, clean this away with an industrial vacuum cleaning or dust pan and brush.