As I embark on more difficult CNC models with interlocking parts, the toughest part about transitioning a design that was meant for laser into one meant for native CNC cutting is realizing the following key facts.
- Each cut with a CNC weakens the board
Unlike laser where there is no resistance, you have a spinning router bit going thousands of revolutions a minute, ripping and pushing through wood. When I first started cutting with my ShopBot Desktop, I’d put in 2-3 screws and for large models, this presented no problem but once you get into small parts with little details, things would get shredded. Now, I’m using over 10 screws into the board and spacing my parts out more so that some strength is preserved long enough in the board till everything is cut.
- Expect a lot more waste
Luckily for me, we got a fire pit in the back, but regardless, I really hate wasting material. With lasers, you have shared cutting lines and every edge can touch the other, saving a lot of money, cutting time and, most importantly, material. People ask me why I use scrap plywood to demo the models you see where on WoodMarvels.com – it’s easy, when there is a lot of waste (and I am prototyping), I’d prefer to be scraping tiling plywood than mahogany boards.
Even using a vacuum to suck-up the dust thrown-up from the spinning bit still doesn’t mean I’d run a CNC in the kitchen… there is dust regardless of how you cut. The vacuum is fantastic and I have noticed a major difference between having it on vs off on not just the cutting surface but also in the air I breath but CNCs belong in the garage, using an old computer for cutting… my production laptop has already suffered from dust once, now this round, I’m looking at alternatives. I’d say the biggest hazard from CNC is dust, while for lasers, it’s fire… pick your poison.
Looking at a laser cut through material is fun for sure, but I find the CNC, even with its precision, is more interesting simply due to the fact that more stuff is moving around. Sometimes a small part gets sucked-up by the vacuum system, sometimes something goes flying if a 3D tab breaks and sometimes, you notice that you have a wonderful 1mm thick skin on the underside of your board after cutting.
So which is better?
My ShopBot Desktop CNC has a lot of advantages, it is cheap to maintain (just need electricity and a 10$US straight 1/8inch double-flute bit) and the entry costs are a fraction from those of laser… but you will waste more material though have lots of fun in the process. As for laser cutting tables, the maintenance and cost of entry are steep and if you blow your tube, you got a huge multi-thousand dollar part to replace (easily costing more than an entire CNC machine by the way) but you can also cut through lots more different types of material, waste less material without dust issues and you can cut much faster with more precision.
As for me, I’d say each has their place in a shop… I have many friends who have both actually and I’d see myself with both as well… and a 3D printer in the middle to keep them apart should a fight ensue.