When you put in and endmill don't put it in fully, the way the collet pulls in it grips the circumference and also pulls in slightly, if its against the stop inside it cannot and will stress the collet. Tape the piece that comes out or leave thin tabs as once its free it can move and destroy cutter, part or both. Your now into CNC routing/milling, nice. 👍
Just my observations on this: The blue painters tape helped. It provides something akin to a "zero clearance insert" on a table saw, in that it provides a counter-force to the lifting action of the tool helping the fiber to shear off. On the larger NEMA 17 motor mount, one side fuzzed a bit more as the tool was doing a "climbing cut" on the inner part and the direction of the fiber was not quite in-line with the cutters tool path, it was a few degrees off. In that cutting scenario, the tool is pulling fibers away from the inner part being cut out. Interestingly that small mis-matched probably helped one side and made the other side worse. You could try reversing the direction of the cut when cutting out the main part to see if that helps. Cheers and Thanks for the video! - Eddy
Tape on wood doesn't help much with tear out if at all in my experience with cnc. It just gums up the mills with adhesive which is very hard to remove. I had better luck with either very sharp end mills, from 5 to 6mm in diameter for milling aluminium or using straight fluted end mills instead of twisted/spiraled flutes. A very light pass with 0.5mm depth of cut often also helps. I've also tried a v bit before milling out a shape, it works but adds an extra tool change. Also, the harder the wood type the cleaner the cuts.
How does tape help use the bit longer? It only adds material for the endmill to go through and the adhesive may prevent heat from dissipating quickly and add friction heating up the endmill more. Tape may well shorten the endmills lifespan.
Josha Beukema a bit that is old and produces ragged edges without tape, will still produce sharp edges with tape. I carve silicon dioxide flooring. Ymmv
You can reduce the fibers from splitting out by considering the rotation of the bit You want to be cutting forward, not trailing - look up climb milling
Have any V bits around? You could use them to cut the surface fibers before using the spiral upcut tool. Woodworkers often use blades for shallow cuts before sawing for the same reason.
Hi, not bad results at all from the 3d printer. Have you considered using tabs with your 'contour' cut out operations in fusion360? When your parts cut through they can come free causing damage to your parts finish or even cause the end mill to break. A little more clean-up but well worth the benefits.
I haven't for this test, but I have in the past. I can add double sided tape under the cutting area which would have the same effect without the need to clean up afterwards. Cheers!
you can cut brass and ally with them but 0.5 mm cuts 0.1 start at i would say 1mm cuts max but not steel maybe mild steel but i dont know but you need carbide tip cutters :P
i didnt expect this to work with a belt drive. I can see the inregularities at first glance 7:54 (no straight lines) If you have an (all) lead screw printer it would be better for the milling. nice idea imho
better to use aluminum but need a CNC machine as someone has already mentioned this below, it is a 3d printer constructed machine that will struggle with deflection issues using it as a CNC machine. cutting circuit boards are an interesting improvisation.
you could do with removing the bottom one the cork mat and putting one of those in instead its only there to draw away heat and better dissipate it across the surface area so !!
Nice video thanks. Instead of battling with filing and sanding my fine plywood engraving jobs I use the back of a cheap kitchen sponge (the Scotchbrite pad like side) to rub the burs right off.
How cool is this? Nice work! I would like to see if it can cut one of those food plastic cutting boards, that will be awesome for making mounts and brackets!
I noticed that too. It may be something to do with the ramp employed by fusion360. It's doing a combination X,Y,Z move in a helical pattern. Maybe for the small helicals there's an issue in code?
As a model maker hobbyist I’m wondering if it would cut through MDF. I want to have a laser cutter but don’t have the money so cutting it on my large bed 3D printer would be awesome. Excellent video. Thank you.
Try estlcam it can generate gcodes mega or uno... You can change the pins out ramps .. .you can generate that code on slicer also... Just make boundary inside or outside (with size of tool diameter) of part you want to make... Generate g code with desired layer height (which will be same as cutting height in z axis) generate gcode open it in notepad and using find and replace find z and replace it with z- & g92 set z0 on top of work workpiece so machine will make moves downward. Spindle motor is always connected to external power on/of switch can be used.
With that small of a bit, you might not be spinning fast enough. Though this is wood and there will always be some sort of burs. If you can, try a larger diameter bit. The results will be better but this is not a 'rigid' setup so you will likely have to decrease your feed rate if using a larger bit. It will all end up being 6 of 1, half dozen of another. If you are looking for better quality cuts though, the slower completion time might be worth it for you.
If you can do 1mm, it doesnt mettar how deep, the only limit is the end mill which depending on the width might be longer or shorter. That at the same time limits wheter ypou can or cannot do aluminium as wider end mills cause higher loads and so your machine might not be capable of doing that.
Hello. I built a super sized version of your hupercube 500mm x 500mm x 500mm. I have to say I love it and thanks for designing it. I have a little issue and I'm wondering if you have seen and fixed it. I was printing 4 quad copter frames and the front corners of the parts are distorted toward the corners. In stead of nice round prop guards in have oval ones but just in the front corners of the build plate. I wrote a little gcode script that moved the print head back and forth and I could see it does an arc not a straight line. Any thoughts? Sure do miss your build videos. It would be great great to see your projects
Make sure the X and Y axis move freely by hand, and do not bind. If the X and/or Y axis movements are sticking anywhere then you won't be printing circles, but arcs as you have found.
You always have nice ideas of what your 3D printer could be doing except 3D printing. :-) However I would recommend a different cutter: Search for parallel milling cutter in Banggood or AliExpress. They are super cheap and do a better job in plywood.
I'm assuming it would do very well, since plywood is a more difficult material to handle. PVC is grainless and pretty soft, so the same mill would make short work of it... It might need different settings to avoid melting maybe. Cheers
For PVC use a different Bit like the one that Tech2 used to make a PCB, you can cut with 1.5mm each pass or even 2.0mm ; The PVC it doesn´t melt as easy like acrylics and some plastics.
Hey Tech2C, great video as always. What do you think would need to be done to the HyperCube (upgrade wise) to enable it to do some light duty aluminum milling? Conductive chips landing on electronics may be an issue.. I't would sure be cool to see one of these making aluminum parts.
Hi Saber, Aluminium will be quite a challenge compared to wood, acrylic, PCB, etc that I have shown so far. Alu is very hard in comparison and would take a lot of force to cut into it. Problems for the Hypercube would be 1) The bed moves up/down in the Z axis and would be pushed down a lot by the drill. The bed springs make matters worse here. 2) The XY_Joiners are plastic and would flex whilst milling the harder aluminium part. 3) The X carriage is plastic too so the drill would deflect as well. And yes the metal chips are an issue too, lol, but we can cover the electronics to protect them. If I were to try, I would mill from the rear of the bed nearest to the Z rails, remove the bed springs so the bed is solid mounted, and move very slowly, down to 2mm/s speed with only 0.1mm Z axis depth of cut per pass.
th-cam.com/video/Rh7VmjOLo0I/w-d-xo.html a question? is it possible that if you have a bowden tube that you let the filament run completely out of the tube through the extruder engine? so that you do not put it in manually, but with the motor! so that you can then turn it all the way back in the tube? again with only the engine! (And with the latest Cura I think it is yet again a bit different!) friendly greetings from The Netherlands! Rob.
1mm/pass when cutting plywood seems like the wrong way to do it. I used to cut 8mm Perspex (using a 1/4" cutter) in a single pass. I would have thought that multiple passes are only needed when cutting metal.
Very nice video! I'm starting my way throug 3D printing and milling, and your videos help SO MUCH! But I still have some questions, though. How do you send gcode to your printer? Do you use a SD card, directly into your printer? Or do you use a computer software? In any case, how do you do it? I tried printing directly using my 3D Cloner Lab's direct SD input, but ended up with everything cranked up. Thank you for your time!
Hi, there, this process is managed by the CNC controller software. The creation of a G-code file is further managed with other graphics software that allows the automated creation of objects to more efficiently create the cutting file. The cutting file is still editable on the controller. This is also known as a CAD-CAM system. computer aided design - Computer-aided manufacturing system. I used to program large scale machines in a factory, I am building my own small machine and also found this video very interesting.
@@Tech2C I was a bit sceptical at first, but it works well and is particularly handy when cutting plastics. It gets the majority of the chips away, preventing them melting and fouling the cutter. I used the STL in Fusion360 to create a new g-code file for the different cutters and material I have.
1/2" ply usually has 5 layers, 1/4" usually has 3. The only differences with marine ply are the types of wood (tropical hardwood) and glue (water and boil proof) that they use.
In most case, converting a 3d printer into a CNC is NOT a good idea. Despite having similar movement type, 3D printer and CNC have very different constructions. First, the mechanics of a 3d printer (bearings) is not protected against dust, this will lead to premature wear and problems. Then, the mecanic, the frame and the transmission aren't stiff enough to cope with very strong counter force and vibrations you have in an CNC, so the cutting quality won't be as good as a true CNC.
those are points to take into consideration, but given the cost of linear bearings (5 bucks for a whole set, 15 if you get good quality polymer bushings which probably aren't really subject to dust problems), you can go through quite a few of them before it begins being more expensive than getting a CNC router. bearings in a 3d printer usually last a lifetime, changing them every couple of years isn't a big deal. for the frame not being stiff enough, it depends a lot on the construction of the printer, and the forces on cutting plywood at this speed are really low. As for the cutting not being as good as a true CNC router, that's fair, but it'll probably be the best 30 bucks CNC router you can get if you already own a 3d printer. note that for pedantry, I'm insisting on CNC router, because the 3d printer is already a CNC.
When you put in and endmill don't put it in fully, the way the collet pulls in it grips the circumference and also pulls in slightly, if its against the stop inside it cannot and will stress the collet. Tape the piece that comes out or leave thin tabs as once its free it can move and destroy cutter, part or both. Your now into CNC routing/milling, nice. 👍
When you cut that square your final layer may move as its being cut so you may leave tabs that can be cut to maintain the location of square
Straight flute endmills make a better finish I have found
Another thing to consider that effects the fuzzies on the edges is when cutting wood you generally want to use climb milling instead of conventional.
Just my observations on this:
The blue painters tape helped. It provides something akin to a "zero clearance insert" on a table saw, in that it provides a counter-force to the lifting action of the tool helping the fiber to shear off. On the larger NEMA 17 motor mount, one side fuzzed a bit more as the tool was doing a "climbing cut" on the inner part and the direction of the fiber was not quite in-line with the cutters tool path, it was a few degrees off. In that cutting scenario, the tool is pulling fibers away from the inner part being cut out. Interestingly that small mis-matched probably helped one side and made the other side worse. You could try reversing the direction of the cut when cutting out the main part to see if that helps.
Cheers and Thanks for the video!
- Eddy
I can see how this would be both easier and better than 3D printing for a number of applications. Great work.
That HyperCube 3d printer is a real Swiss army knife!
swiss army 3d printer lmao
Tape on wood doesn't help much with tear out if at all in my experience with cnc. It just gums up the mills with adhesive which is very hard to remove. I had better luck with either very sharp end mills, from 5 to 6mm in diameter for milling aluminium or using straight fluted end mills instead of twisted/spiraled flutes. A very light pass with 0.5mm depth of cut often also helps. I've also tried a v bit before milling out a shape, it works but adds an extra tool change. Also, the harder the wood type the cleaner the cuts.
Josha Beukema tape allows me to use the bit longer, without fuzzy edges, but you do need to scrape the junk off between cuts.
How does tape help use the bit longer? It only adds material for the endmill to go through and the adhesive may prevent heat from dissipating quickly and add friction heating up the endmill more. Tape may well shorten the endmills lifespan.
Josha Beukema a bit that is old and produces ragged edges without tape, will still produce sharp edges with tape. I carve silicon dioxide flooring. Ymmv
You can reduce the fibers from splitting out by considering the rotation of the bit
You want to be cutting forward, not trailing - look up climb milling
The cleaned result looks amazing! Nice work!
Cut plastic breadboard (kitchen cutting board) instead of the ply. It's pretty good for thermal stability and you can buy it almost anywhere.
Have you considered adding a vacuum line? Seems like it'd be a big help in keeping material shavings out of the motion system.
Have any V bits around? You could use them to cut the surface fibers before using the spiral upcut tool. Woodworkers often use blades for shallow cuts before sawing for the same reason.
I have very narrow V bits but they're probably too small. Good idea though.
Hi, not bad results at all from the 3d printer. Have you considered using tabs with your 'contour' cut out operations in fusion360? When your parts cut through they can come free causing damage to your parts finish or even cause the end mill to break. A little more clean-up but well worth the benefits.
I haven't for this test, but I have in the past. I can add double sided tape under the cutting area which would have the same effect without the need to clean up afterwards. Cheers!
you can cut brass and ally with them but 0.5 mm cuts 0.1 start at i would say 1mm cuts max but not steel maybe mild steel but i dont know but you need carbide tip cutters :P
i didnt expect this to work with a belt drive. I can see the inregularities at first glance 7:54 (no straight lines) If you have an (all) lead screw printer it would be better for the milling. nice idea imho
All Good - Can you give the GCode for above cut of this PLY wood sample as same - i need this
How the hell did you find a flat sheet of ply at Bunnings?!!???!!!
And got it cut somewhere near the actual size he asked for.
better to use aluminum but need a CNC machine as someone has already mentioned this below, it is a 3d printer constructed machine that will struggle with deflection issues using it as a CNC machine. cutting circuit boards are an interesting improvisation.
two questions.... would this work with any 3d printer and how would it do cutting something like pine or oak?
I'd add a mechanical stop block so you absolutely can't reach your bottom plate. Be careful if you use a longer bit later on. Don't ask me how I know.
Nice job - the ply cutouts would look great with a layer of clear polyurethane paint.
Yes they would look great with a coating. Maybe an idea for another video... ;)
Cool ! Did you ever consider doing a hobby pick and place cnc machine for smd prototypes? No easy but a super diy project!
Nice. Makes me want to give it a shot
Cover the plywood with sticky shelf paper to reduce the splintering if its an issue
Excellent videos. I've been following this channel since the early days with your prusa. Keep on posting regularly.
you could do with removing the bottom one the cork mat and putting one of those in instead its only there to draw away heat and better dissipate it across the surface area so !!
Awesome. What do I use to generate the g code?
Nice video thanks. Instead of battling with filing and sanding my fine plywood engraving jobs I use the back of a cheap kitchen sponge (the Scotchbrite pad like side) to rub the burs right off.
How cool is this? Nice work! I would like to see if it can cut one of those food plastic cutting boards, that will be awesome for making mounts and brackets!
If the wood was thinner do u believe it will crack?
Why do you think the 3mm holes weren't round while the larger holes looked perfect?
I noticed that too. It may be something to do with the ramp employed by fusion360. It's doing a combination X,Y,Z move in a helical pattern. Maybe for the small helicals there's an issue in code?
Check the toolpath and see if you're using arc moves
As a model maker hobbyist I’m wondering if it would cut through MDF. I want to have a laser cutter but don’t have the money so cutting it on my large bed 3D printer would be awesome.
Excellent video. Thank you.
Hello, yes MDF would be just as easy as plywood. Just be sure to use breathing protection as MDF dust contains toxins.
Tech2C thank you for your reply and the tip. I’ll be sure to stay out of the room when it’s been cut, I will keep the window open and use a fan.
I love your channel and all the cool videos and stuff your doing with your printer
Thanks dude!
On what software (i mean like a slicer) did you run the gcode to the 3d printer?
How about printing a 3d model then milling it to get a perfect smooth surface ?? What do you think ?
Hi.
Great video. Thought to try minimise wood fibre. Use a thinned matt varnish or sanding sealer to bind fibers so they cut better maybe.
Do you have a workflow on the software side of things, like how you load gcode to the 3d printer.
Try estlcam it can generate gcodes mega or uno... You can change the pins out ramps ..
.you can generate that code on slicer also... Just make boundary inside or outside (with size of tool diameter) of part you want to make... Generate g code with desired layer height (which will be same as cutting height in z axis) generate gcode open it in notepad and using find and replace find z and replace it with z- & g92 set z0 on top of work workpiece so machine will make moves downward. Spindle motor is always connected to external power on/of switch can be used.
With that small of a bit, you might not be spinning fast enough. Though this is wood and there will always be some sort of burs. If you can, try a larger diameter bit. The results will be better but this is not a 'rigid' setup so you will likely have to decrease your feed rate if using a larger bit. It will all end up being 6 of 1, half dozen of another. If you are looking for better quality cuts though, the slower completion time might be worth it for you.
Thank you, your CNC tutorials are great !!!
3mm aluminum?
If you can do 1mm, it doesnt mettar how deep, the only limit is the end mill which depending on the width might be longer or shorter. That at the same time limits wheter ypou can or cannot do aluminium as wider end mills cause higher loads and so your machine might not be capable of doing that.
Even 1.6mm or 2mm aluminum?
if it can do aluminium in 0.1 passes good enough, it will only take you 16 to 20 passes
@@robinc.5077 Thanks. Which router?
Hello. I built a super sized version of your hupercube 500mm x 500mm x 500mm. I have to say I love it and thanks for designing it. I have a little issue and I'm wondering if you have seen and fixed it. I was printing 4 quad copter frames and the front corners of the parts are distorted toward the corners. In stead of nice round prop guards in have oval ones but just in the front corners of the build plate. I wrote a little gcode script that moved the print head back and forth and I could see it does an arc not a straight line. Any thoughts?
Sure do miss your build videos. It would be great great to see your projects
Make sure the X and Y axis move freely by hand, and do not bind. If the X and/or Y axis movements are sticking anywhere then you won't be printing circles, but arcs as you have found.
all that runs a full size one is a belt pulley motor and chuck you're just scaling down :)
Great job, man. Your presentation is excellent, I would say, professional quality.
Curious as to whether it would do that extremely thin tin that they make duct work out of...
Please upgrade videos? Does TL-Smoothers work?
You have got such a wonderful voice!
where can i Get this Spindle system?
I suspect you might actually want a down cut because the bottom surface is supported by the piece underneath.
I second that. First thing I thought when I saw the uplift on the cut after the dust was cleared away.
Nice video! try a sacrificial scrap of thin ply on the top instead of blue tape.
Good idea. I'll also have 2 copies of it then too ;)
What software did you use to generate the gcode ?
Witch spindel do you use ?? plz give link...Thanks
What speed was the spindle running at please?
Max speed. It's a small dremel style rotary tool.
ok thanks
You always have nice ideas of what your 3D printer could be doing except 3D printing. :-) However I would recommend a different cutter: Search for parallel milling cutter in Banggood or AliExpress. They are super cheap and do a better job in plywood.
Ok found them on Banggood. I've added them to my wish list for next purchase, cheers!
What other types of wood soft like Pine? medium hard Oak or hard Eucalyptus?
I'd say that would be fine.
Looks perfect!
Great work
How would this do with PVC sheets?
I'm assuming it would do very well, since plywood is a more difficult material to handle. PVC is grainless and pretty soft, so the same mill would make short work of it... It might need different settings to avoid melting maybe.
Cheers
For PVC use a different Bit like the one that Tech2 used to make a PCB, you can cut with 1.5mm each pass or even 2.0mm ; The PVC it doesn´t melt as easy like acrylics and some plastics.
Would you recommend doing the same thing but with acrylic?
Yes th-cam.com/video/ILnc-7I0zQA/w-d-xo.html
Hi!! How do you create the gcode?
Which screwdriver is that? I really like that one. I have been looking for ages for one I like.
It's a ball hex screwdriver.
Cracking job as usual. Would like to see the software side of how you did it ?
His earlier videos go over it
Just seen it thanks
Hey Tech2C, great video as always. What do you think would need to be done to the HyperCube (upgrade wise) to enable it to do some light duty aluminum milling? Conductive chips landing on electronics may be an issue.. I't would sure be cool to see one of these making aluminum parts.
Hi Saber, Aluminium will be quite a challenge compared to wood, acrylic, PCB, etc that I have shown so far. Alu is very hard in comparison and would take a lot of force to cut into it. Problems for the Hypercube would be 1) The bed moves up/down in the Z axis and would be pushed down a lot by the drill. The bed springs make matters worse here. 2) The XY_Joiners are plastic and would flex whilst milling the harder aluminium part. 3) The X carriage is plastic too so the drill would deflect as well. And yes the metal chips are an issue too, lol, but we can cover the electronics to protect them. If I were to try, I would mill from the rear of the bed nearest to the Z rails, remove the bed springs so the bed is solid mounted, and move very slowly, down to 2mm/s speed with only 0.1mm Z axis depth of cut per pass.
Thanks for the reply. When i get around to building my hypercube some day maybe i'll look into remixing it with some of these design considerations.
th-cam.com/video/Rh7VmjOLo0I/w-d-xo.html
a question?
is it possible that if you have a bowden tube
that you let the filament run completely out of the tube through the extruder engine?
so that you do not put it in manually, but with the motor!
so that you can then turn it all the way back in the tube?
again with only the engine!
(And with the latest Cura I think it is yet again a bit different!)
friendly greetings from The Netherlands!
Rob.
Incredible video thanks for sharing !
I see you finally had to replace the carbon fiber rods. Did they wear down?
Also the flexible shaft was an amazing idea.
He said something in a previous video about them not being stiff enough for milling.
That's right, for CNC purposes I switched to the heavy steel rods for extra stiffness. The carbon tubes will go straight back on for 3D Printing...!
I've been using a flex shaft on my 3D printer for about two years for PCB CNC drilling
@@Tech2C Make a test between the two types to figure out if it makes much of a difference!
You could go much larger diameter rods and still be much lighter than steel. Why not 16mm carbon?
What software do you use ?
very, very good congratulations for the job.
You should make a computer case in plywood or a raspberry pc case.
Good idea!
1mm/pass when cutting plywood seems like the wrong way to do it. I used to cut 8mm Perspex (using a 1/4" cutter) in a single pass. I would have thought that multiple passes are only needed when cutting metal.
that's a really flimsy setup, and more of a proof of concept than a real thing, still something that can be kept in mind while pushing the limits.
Very nice video!
I'm starting my way throug 3D printing and milling, and your videos help SO MUCH!
But I still have some questions, though.
How do you send gcode to your printer? Do you use a SD card, directly into your printer?
Or do you use a computer software?
In any case, how do you do it?
I tried printing directly using my 3D Cloner Lab's direct SD input, but ended up with everything cranked up.
Thank you for your time!
Hi, there, this process is managed by the CNC controller software. The creation of a G-code file is further managed with other graphics software that allows the automated creation of objects to more efficiently create the cutting file. The cutting file is still editable on the controller. This is also known as a CAD-CAM system. computer aided design - Computer-aided manufacturing system. I used to program large scale machines in a factory, I am building my own small machine and also found this video very interesting.
Hey, this was an amazing video, congrats! I subscribed
HHHNNGGGGG!!! Omg every time this vacuuming is the bomb
cool i want too create cnc machine
Incredible video thanks!
Is there anyway we could work together I have a hypercube design I would like to run by you. I could use any advice and knowledge you could pass on.
Eliminate the fibres by estapoling the timber first.
great job
Nice! Can it cut metal tough?
Yes. It can cut Aluminum foil.
Great stuff. Thanks!
incrase the speed decrease the depth. you will have better result
That drilltype chuck is absolute garbage. It'll introduce runout that'll change all the time. Those tight tolerance collets are by far better choice.
1mm Z Stepping is way too much
Have you thought of trying a bit fan?
blog.bantamtools.com/introducing-the-bit-fan-a-new-othermill-accessory-you-can-make
Wow no I haven't! Thanks for sharing :)
@@Tech2C I was a bit sceptical at first, but it works well and is particularly handy when cutting plastics.
It gets the majority of the chips away, preventing them melting and fouling the cutter.
I used the STL in Fusion360 to create a new g-code file for the different cutters and material I have.
save money on x2 sided tape by sticking masking tape on both surfaces and superglue them together
Cline milling against the grain with a machine makes it judder sum times make minute cuts
Wow thats amazing! Cutting wood is realy cool, but can it cut metall?
cool ... thank you
ooh, DnB, nice
Perfect!!!
I think you have a competitor.
if they sold you that as marine 6mm plywood….. they are worng… real marine plywood has like min of 5layers
1/2" ply usually has 5 layers, 1/4" usually has 3. The only differences with marine ply are the types of wood (tropical hardwood) and glue (water and boil proof) that they use.
Anything but 3d printing. Like using a spanner for a hammer... cheers!!!! I would use a scroll saw or band saw any time.
In most case, converting a 3d printer into a CNC is NOT a good idea. Despite having similar movement type, 3D printer and CNC have very different constructions. First, the mechanics of a 3d printer (bearings) is not protected against dust, this will lead to premature wear and problems. Then, the mecanic, the frame and the transmission aren't stiff enough to cope with very strong counter force and vibrations you have in an CNC, so the cutting quality won't be as good as a true CNC.
those are points to take into consideration, but given the cost of linear bearings (5 bucks for a whole set, 15 if you get good quality polymer bushings which probably aren't really subject to dust problems), you can go through quite a few of them before it begins being more expensive than getting a CNC router. bearings in a 3d printer usually last a lifetime, changing them every couple of years isn't a big deal. for the frame not being stiff enough, it depends a lot on the construction of the printer, and the forces on cutting plywood at this speed are really low. As for the cutting not being as good as a true CNC router, that's fair, but it'll probably be the best 30 bucks CNC router you can get if you already own a 3d printer.
note that for pedantry, I'm insisting on CNC router, because the 3d printer is already a CNC.
I don't think my Bunnings will cut down to those small ply squares.
Meh. Very low quality plywood. 6mm must have 5 layers.