CNC router construction materials

[justin22885]

im wondering what materials an accurate CNC router could be made of?... MDF, steel, aluminum, HDPE, what about wood, or a large thickness plywood? (like 1 inch?), would it be possible to use these materials as well, and still achieve the same accuracy as an MDF machine using similar designs?

has anyone built a machine of this size out of rectangular tube steel welded, perhaps with tube or plate steel gantry? if so.. what did the steel cost you to build it?... id assume oversizing the steel frame, with some cross braces of slightly smaller diameter to give sort of a set in area to lay a piece of MDF or plywood for the table would be the way to go... weld on the angle iron rails and from there it comes down to gantry design... im going to the hardware store this week to check prices on square tube steel, small diameter i beams, and plate steel to get an idea of what a steel machine would cost... would yield a much stronger machine than mdf or plywood, and might not cost too much more.. so it could be worth it (if you have access to a welder)

if i cant do that im thinking of making the table frame out of 4x4 wood, braces with 2x4 wood, with a 1" thick plywood gantry...

i just dont think anyone anywhere near me carried MDF, so im keeping the options of alternatives open

im looking to build a machine with 48x24 inch travel, i believe that short, leadscrews all around should do fine... i probably wont need to use a chain driven X axis until i build a machine with a 4x8 foot machine later...

so im thinking of using a design SIMILAR to joes.. but not exactly... i think usnig fully supported angle iron rails for the skate bearings to slide on might be better, and easier to put onto the machine

extreme precision is nice... but really not as important for what ill be using the machine for as other things people could use them for, im a luthier, so ill be using it to cut wooden guitar parts which will still need to be sanded and refined anyway

[degreaser]

Here's one with which I'm in the very early stages of fabrication. Table size is 66"x42" with 8" nominal Z axis travel. The base is being built from 2x2x3/16 steel tube. The router itself is 2x2x1/4 and 2x4x1/4 tube and lots of 2x1/4" flat bar. Motor/bearing mounts and the Z axis are constructed of 6061 aluminum. Completed it will weigh in around 1000lbs. Gantry weight will be around 120lbs. The X and Y axis are #2 v-bearings on 3/4" angle, the Z axis is an ebay special 20mm THK linear bearing. I'm using 5/8" Roton ballscrews with dual preloaded ballnuts and nema34 servos with 4:1 belt reduction. The router will consist of welded sub-assemblies which will be bolted together. The base will be nearly 100% welded. At some point I'll upgrade the X and Y axis to THK or equivalent as my budget permits.

I haven't started a build thread yet. Soon. Gotta make the garage presentable for photos . Right now I'm making parts and drilling countless numbers of holes for the various router frame sub-assemblies. I'll fire up the tig when I get most of the cutting, drilling and tapping done.

As far as getting materials, here in Reno I get steel from PDM Steel. They have outlets in California as well. Forget the hardware stores as the markup will be 400% if not more and your selection will be very limited. Find a local steel supplier. The steel for this build was a little over $1K including cut fees.

Building a Joe's 4x2 hybrid would certainly be cheaper and a whole lot easier. Personally, I like steel

[justin22885]

well ive decided to use MDF for the first router.. just a really cheap, simple build... my second router will be a small one, not a tower gantry but one that sits on elevated walls, with a sunken table, itll be for doing steel mostly, but my third one will be a steel constructed much, much larger table, and id really like to use the gantry design in your drawings.. i like it

[ger21]

Originally Posted by justin22885 if i cant do that im thinking of making the table frame out of 4x4 wood, braces with 2x4 wood, with a 1" thick plywood gantry...

A 1" Ply gantry might be too flexible, and you'll probably get a lot of warping with 2x4's and 4x4's.

[beone]

Mine is all 1/2 ply torsion boxes. working great after 2 1/2 years
Dave

[degreaser]

Originally Posted by justin22885 well ive decided to use MDF for the first router.. just a really cheap, simple build...

I would imagine you've probably seen it but there's a very nice example of an MDF router here: http://www.cnczone.com/forums/showthread.php?t=68771

[justin22885]

that is a really nice MDF router... i plan to make one like that eventually to replace the one i have now, but ill use plate steel for that future build.. the one ill build first i might use a similar gantry design but a smaller table... should be able to make it out of 1 sheet of MDF

was this done with a single 4x8 sheet of MDF?

it would be PERFECT if the router could travel a full 4x8 feet

[justin22885]

i really liked the machine degreaser showed me.. it gives me some ideas im going to incorperate into a much more simpler, yet far less aesthetic design...

difference is ill probably use a chain drive for the X axis, and 3/4 inch plywood for the table, and possibly a 4x4 pine frame with legs with 2x4 cross supports under the table.. the 4x4 frame should give me a bit of added width, allowing the machine to travel a full 48x96 inches... so it can carve an entire 4x8 foot sheet of material....

yeah, that sounds best

[laldrich10]

I am going to use 8020 to start. Its the industrial erector set. It should be easy to get every thing straight and smooth opperating. It may cost a little more but will be a lot simpler.

[degreaser]

http://www.finelineautomation.com has a 2'x3' router kit based on 8020 for a very reasonable price. It looks like a very quick way to get something up and going. It's offered by a couple of guys here on cnczone.

[justin22885]

theres a website.. forget what it is.. but it takes you through all the steps neccessary to build a very simple CNC router, even shows a nice chain drive mechanism... im going to build that much simpler gantry, but support that gantry with the Y axis from the other forum thread, and widen it out to cover a 9x5 table, giving me an 8x4 cutting area

the table will be 3/4 inch plywood, cross braces about every 8 inches under the table, and probably an MDF gantry, depending on the cost

since this will be a rather.... long machine for leadscrews, im either going to use a chain drive mechanism (which works a lot like a rack and pinion, but it walks along a chain)... or that rotating nut design in the link degreaser first provided... either way it looks like the X motor will be attached to the gantry

[justin22885]

thing is though.. ive decided to make a plywood base frame, well supported, MDF table, and MDF gantry for a router table with a 4x2 foot travel, since im a luthier, guitars are my first priority, and then i can take the time and profits to make a much, much nicer router of 4x8 size since id be able to use the origional one to cut better, more elegant pieces of wood, have more time to design the specifics of the rails, drive mechanisms, and solidworks the entire project of my own design...

but first, ill just do a simpler, easier, much cheaper 4x2 plywood/mdf design, and after that im doing a small 3x2 or even smaller 2x1 design made of square tube and plate steel.... but without the tall gantry.. the kind with the walls where the gantry rides on top of those walls, since its a much stronger design, and machine 2 will be for steel :-D... .number 3 will be the 4x8 model