New member from Trinidad

Hello all.

My feel of employment is not surrounded CNC Machine but I became interested in this due to the fact that am a freelancer and always have time on my hand. I have a woodworking background through school but never follow through with it although having a love for it.

Seeing that it is an issue to import a CNC router all the way to Trinidad, I have decided to tackle building one myself. My intentions is to build a 8'x4' CNC Router, where I can place a sheet of MDF/ply to make children chairs, tables etc To gain a little extra money in my pocket, and expand to a full woodwork shop by mid next year, I have gone through many sites/you tube/ the treads you fellas placed. Most of what you fellas talk about eg. the servo/stepper motors is really new to me. I understand that it will not be an easy road but I am willing to go the distance with this project.

So far I have seen one 8'x4' CNC that I am very much interesting in building from the treads of D-Man. The steel frame will be easy to get here whereas the rest I may have to import. I was looking around on how to PM someone but with no luck. Any assistance will be appreciated.

Regards

Hi and welcome to the forum Trini. To send a PM to someone you have to left click on their name and select private message (that is if they have set their profile to allow private messages!) Best thing to do is as you are currently doing, look around, see what others have done. I'd suggest looking at Kingcreaky's build here as that's the size you want. once you've had a look, made some notes etc. get your pen and paper out (or better use Sketchup or similar) to do some rough drawings. put them up on here for people to critique/advise and then go for there. Don't even think of sorting the electrics until you've got the basic frame designed as the electrics will depend on your design....

Good luck and welcome to the forum!!

Welcome trini,

Don't let me put you off but if this is your first CNC machien then starting with a large machine isn't always a good idea.
While it may seem like not much more work for large machine compared to smaller size this isn't the case in reality. There's hell of a lot more work and it's much harder to get a large accurate machine. Design and build quality become much more important.

Every thing Neil suggests is good advice you should listen too but please be aware of the scale of machine your undertaking. Just because others have built large a machine doesn't mean that machine performs good or couldn't be better with just a few small tweaks.!! . . . So Research then research some more then a little more for good measure before starting.

hi

Thanks for the welcome. Yes I will go through Kingcreaky's build. I have downloaded the sketch up program. I was getting ahead of my self with the electronics. But after many reviews of others I see that the frame has a lot of work also.

So thinking about where to start, I was wondering how much over the dimensions should I go. Eg. I am designing for an 8'x4' cutting area so recommended dimensions should be just a one or two inches over 8'x4' or must the top area be to exact 8'x4'? Also I would like to know the different rails to use. I would like to design up to the rails. I see that many people used the SBR bearings. What are your taught on this calibre of machine.

regards

hi.
I have a sketch from sketchup. How do I change it to a photo too upload?

Under "File" select the "Export" option and then "2D Graphic" and it will export whatever is shown on your screen.

ok here goes.
I have played around a bit with sketch-up. This is what I have so far.Attachment 16549Attachment 16548Attachment 16547. I would like for you all to over look it and add any suggestions. My plan is to design around the equipment I would use on it.
Plans on using
1] 4 pcs Nema 34 stepper motor 1600 oz.in bipolar with single shaft 4 pcs Stepper motor driver DM860A, peak 7.8A, 24-80VDC 4 pcs Power supply 350W 60V 1 pc Breakout board & 1 pc parallel cable. [ will buy from amazon]Attachment 16550

2] CNC KIT FROM AMAZON LIST BELOW

1 x RM1605--300mm ballscrew ball nuts + end machined for end support bearings(BK/BF12)
1 x RM1605--1750mm ballscrew ball nuts + end machined for end support bearings(BK/BF12)
2 x RM1605--3000mm ballscrew ball nuts + end machined for end support bearings(BK/BF12)
4 x BF12/BK12
4 x 6.35*10mm coupling
2 x SBR20--300mm liner rail
2 x SBR20--1750mm liner rail
2 x SBR20--3000mm liner rail
12 x SBR20UU
Note: The ballscrew kit is C7 standard with standard machine end.
All the length of the ballscrew and liner rails kit can be cut at any length.

I have not pick the spindle yet, to design around it. So any design ideas you fellas have would be nice to hear them. Also I would like to know what other electronics I would need, so I can budget my spending and source them while I do the rest of the build. I was thinking about appox $3000 to $4000 U.S.

OK, frame looks not a million miles away, I'd make sure that the top rail has a thick wall otherwise it'll resonate with high frequency vibrations from the spindle. Bed looks like it could do with a bit more bracing.

Electrics, don't buy a "kit" of parts from one seller as they're always compromised in at least one area. If you're going to use Nema 34 motors (Z axis won't need it unless you're planning a monster?!!) then they need at least 100V to make them perform, best to use a 230V driver to get the best performance. If you're determined to use lower power drivers then use ones that can take 80V and build your own power supply to get the best performance.

Ballscrews, for wood you'll need speed so I'd use 1610 ballscrews on your X & Y axis and 1605 on your Z only. But at this length you'll need rotating ballnuts on a fixed (clamped both ends) 1610 ballscrew. Otherwise you'll need to go up to 20mm ballscrews and possibly 25mm, couldn't say which without doing the calcs for speed etc.

Couplings, use belts, this enables you to swap pulleys to increase/decrease the speed/resolution and more importantly it stops resonance being transmitted to the stepper motors.

Spindle, you can't got wrong with a 2.2kW water cooled spindle with inverter, the type you get from eBay....I've got one and they're great!

Other electronics will be things like relays and other electronic components (fuses, din terminals etc. etc.) to build your control panel, limit switches what controller are you thinking of?

For the frame I know there is a lot more to be done on it. I understand of what you said about the thicker top rails and I will make a note of that.

As I said before am really new to all of it and I was under the impression that all motors will be the same to have easier setup. But if that is not the case I would be glad to go with something smaller for the Z axis. When its comes to the drivers and power supply I rather buy these with the advice I get from you all. It will be a bit more money but will be faster to have the build started up early next year.

With the ball screw, yes I do want speed, and I will put those you suggested in my list of stuff I will need. But when it comes to the 20mm and 25mm ball screws I don't know how to cal such.

The belt I was more thinking of that but I hit a stop when assembling and tension of such came into play. I don't know how to design that section of it.

I will also put that spindle into my list. When that time comes for me to buy anything I will post up my list to make sure I have everything in order.

When you say other electronics, I did not dig into it due to the fact that, I taught when I buy a kit I would attained all of this. But as you mentioned, there always compromised in at least one area. So I will need some help with that if you all don't mind. When you say the controller, do you mean the breakout board?

good day all

Its been a while since i haven't posted anything. After reading a lot more threads i realized i was getting ahead of myself. I have worked on the design a little bit see pics. Also i have decided to put a 4th axis. But this is something i will need help in applying it to my current design. I don't know how to upload my sketch-up to the site. Have a look and tell me what you all think.

Attachment 17698Attachment 17699Attachment 17700Attachment 17701Attachment 17702Attachment 17703Attachment 17704Attachment 17705

If @ all possible ie budget wise i would change your linear rail system to Hiwin or similar profile. X axis top rail put another two pieces (each side) between frame to brace. Z axis it is best practice to use the rails on the front plate to provide additional support.
regards
Mike