Can you use the same tooling to cut both plywood and MDF on a CNC saw? There’s no definitive answer, as indicated by the mixed responses to this woodworker query in the recent Shop Smarts challenge.
More than 150 woodworkers gave their input on January’s Shop Smarts challenge, presented by Woodworking Network and sponsored by Saber Diamond Tools. In a randomly selected drawing, Sean Ferguson of Ferguson Custom Woodworking won a $100 Visa gift card from Saber Diamond Tools for this helpful response:
“Simply put, yes. It all depends on what type of tooling you have installed and what type of plywood you are cutting. I have run a CNC beam saw, where we cut all sorts of materials with the same high-quality tooling, based on production efficiency alone. However, if you were cutting expensive, high-quality plywood, I would go with optimized tooling. Blades that feature a high ATB, slice through the veneers, virtually eliminating tearout. Better yet, utilize your saw's scoring blade to all but eliminate tear out, on the bottom edge, if so equipped. As far as MDF is concerned, you can cut it with practically any tooth geometry, but results will vary. The trick with MDF is using tooling that can withstand the abrasive quality of it. We commonly used tooling with a TC grind, to ensure the longevity of the cutting edges.
“The question will ultimately come down to how much of each material you want to cut. If you have very little MDF, use a blade that will perform favorably with the plywood and hold up to the MDF. If you have a lot of MDF, use tooling that is robust enough to handle it, but will provide acceptable results with the plywood. In the end, I would let the plywood dictate the tooling. Expensive plywood for a high-quality product – change your tooling to get the best results. Decent plywood where tearout can be dealt with – try using the same tooling,” Ferguson said.
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Other notable suggestions included:
Can use the same tooling, but may not be as efficient
“You can use the same tool if the tool is something like PCD. Your will get very long life of the tool and still provide excellent high-quality machining.” – Christopher Reil, ONG Solutions
“We use the same tooling. A second pass cut after onion skinning the first cut works great.” – Jon Taylor, RC Taylor Inc.
“We use the same tooling all the time to cut both plywood and MDF. We use a half-inch mortise compression bit running at 15,000 rpm with a 800 ipm feed speed. – Justin Ritchhart, AF Johnson Millwork
“You could but it would not be as efficient as using the proper tooling for the material being machined.” – Doug Foley, Cherry Creek Woodworking
“You can cut both MDF panel product and veneer core panel product with the same tooling, but the MDF panel product will dull the tooling more quickly than the veneer core panel products. This is due to the high content of adhesive in the MDF panel product. To deal with this problem you should have tooling for the MDF and tooling for the veneer core panel. This will allow you to purchase tooling for the veneer core panel that is specifically design for the product. The tooling should have a geometry specifically designed for the species you generally cut. This will increase the tooling life for the veneer core by 2X's and allows you to use the original tooling for MDF core panel products.” – Mark Smith, Morris Community High School
“You can use the same tooling providing the tooth geometry, number of teeth and rake angle are correct. It is possible to get chip free cuts with this combination and also RIM and feed speed compensation.” – Bob Barone, Precision Drive Systems
“Yes, you can use the same blade when cutting plywood and MDF on a CNC panel saw. Best blades to use with these two materials are triple chip grinded blades (TCG) or Alternate Top Bevel (ATB) with 10-15 degree hooks. In addition to that, the more teeth the better the cut will be. No shop wants to be changing out a blade in a CNC panel saw with every change of material. The cost of labor would be astronomical if this was the case.” – Nicole Pinsonneault, Conestoga College
“Depends on if you are using diamond tooling or carbide tooling. The plywood would be hard on the diamond but great on the MDF, so if that is the case I would change tooling. If you are cutting with just carbide it would be fine on both, whether it be insert or carbide tip tooling.” – Kevin Austin, Imperial Woodworks
“The simple answer is yes. But we must dig a little deeper to understand why. First, the densities of each product differ. Obviously MDF is much denser than plywood. MDF pulls harder (harder on the tool to cut) than plywood. This can change how the tool cuts the material. MDF ruptures while being cut and plywood shears. Second, and possibly the most important consideration, is how the products are made. Plywood is multiple thin layers bonded together with an alternating grain structure, while MDF is a wood "pulp" pressed together. The adhesive used to glue MDF is similar to a clay, which is abrasive. This abrasiveness causes more tool wear when cutting or milling MDF. So now we know there is a wear issue with MDF. You must watch the quality of cut during milling and be aware the signs of a dull tool. If you primarily cut MDF, tool wear will be accelerated. Both products will be cut nicely with the same sharp cutter. Change the cutterhead more frequently if you decide to dual purpose your cutters.” – Austin Burgess, GRB Construction
More tooling tips:
“The same tooling can be used, although the feed rate and spindle speed may need to be adjusted.” – Nathan Haskell, Watson Wood Works
“If I'm making perimeter or edge cuts, I will use a 3/8-inch or ½-inch straight cutter. I will also tell the machine to oscillate the bit, 2 or 3mm, so I maximize the use of my cutting edge. With the plywood, if I need to crosscut, I’ll drill an 8mm or 10mm thru hole first at the point where my cut will end, to eliminate tear out.” – Ryan Shavitz, RLE Millwork
“The tooling that you would use on plywood will become dull much faster cutting MDF, but it will work. If you are cutting a lot of MDF, you should change tooling for cutting the two different materials.” – Mark Kamprud, Vertex Group
“You can use anything you want. It's your choice, but if it comes to quality of the cut, that is why there are so many different types of blades available. I'd use a combination blade if retooling isn't something you don't want to go through.” – Stephen Smith, SAS Creative Woodworks
“For use on plywood we use a compression bit so it will cut from both cover veneers inward and for MDF we use a straight cut bit.” – Mike Welch, Stillwood Doors
Reasons to change tooling:
“You will need to change tooling. The MDF will quickly cause the tool to cut the plywood poorly. The tool will still be fine for cutting MDF.” – Jody East, Wellborn Cabinet Inc.
“MDF is much harder on tools than plywood due to the density and the process of separation, (plywood sheers while MDF ruptures), and the glues that are used. You should use a blade that is designed for MDF or Plywood respectively.” – Steven Donovan, Rustic Creations
“Since MDF is made of so many different composites than plywood I would recommend changing them.” – Robert Brennan, Bob’s Woodworking
“No, once you run MDF past any blade it dulls it very quickly. This doesn't affect the MDF cutting, but it greatly affects the cutting of the ply. Different blades/cutters should be used for different materials.” – Josh Okeson, Custom Creative Furniture
“I don't have a CNC machine, but it would probably be wise to use different blades for each material. The glue in MDF can dull a blade/bit in no time. Just a little shop guys answer! Good luck.” – Jeff West, Westco Woodworks
“I would recommend NOT. MDF will cut very good with triple chip teeth in the main blade. Good plywood cutting should have alternate top bevel teeth in both the main and scoring blades, especially when cross cutting the wood grain.” – Dwayne DeWhitt
“Of course you would want to use different tooling. Just as table saws will need different blades, so will your CNC saw. The plywood has more fibers that will bog down a blade designed for MDF. This will create heat and will reduce the life and cut quality.” – Scott Vernem, Taylor Inc.
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