Cheap X/Y/Z gantry?

[8086]

So, following the discussion in another thread on homebrew pick and place machines, and being someone who uses SMT parts on a regular basis, I thought I might look into having a go at one myself. 

I'm looking for a starting point - just a simple, cheap as possible, but not totally shitty, X/Y gantry (and Z but not essential) for around £200 or less. Including motors would be good but again not essential.

I figure I may end up needing to produce my own, with the limitation that the gantry itself needs to be mobile, to pick components - can't just move the bed in this case. So far the only cheapy cnc kits I have found are all with a fixed tool and moving bed...

If anyone knows of a cheapy X/Y gantry system with fully mobile axes then I would love to hear about it - it only needs to be basic, as it will promptly be altered and bits added on etc.

Hopefully someone here has something they can share - and I don't mind if it's not a UK supplier. I'm after anything. Thanks

 

[mikeselectricstuff]

An old X-Y plotter may be a good start.  Clearance between pen-holder and bed can be an issue though.

[JoannaK]

Surface mount parts are usually quite flat, so there's not much need for z-axis movement. And if there's need for extra clearance, one migth want to make PCB-size hole (dent?) to the bed.

[GeoffS]

Check out  this forum. UK based and CNC oriented.
Helpful and knowledgeable bunch of guys.

[8086]

I found a couple of old Roland XY Plotters but they look a little too flimsy to support anything more than the pen they were designed to use 

I also found this, though: http://www.ebay.co.uk/itm/NEW-3020-DESKTOP-ROUTER-ENGRAVER-DRILLING-MILLING-ENGRAVING-MACHINE-CNC-h3-/320854363030?pt=UK_BOI_Metalworking_Milling_Welding_Metalworking_Supplies_ET&hash=item4ab4690b96#shId

Now, it's fairly expensive, and would have most of the electronics replaced, but for the hardware, what do you guys think?

[GeoffS]

I think you'd find the 3020 a bit too slow for a pick and place.  You need something that is fast and fairly light weight as it won't have a heavy load to move about.
If I was building something from scratch, I'd look at using something like Makerslide. This is used in DIY laser engravers/cutters and in at least one 3d printer.
If you want to check out linear bearings and ball screws, have a look at Marchant Dice

[ecat]

Another vote for http://www.mycncuk.com/

Especially http://www.mycncuk.com/forums/other-cnc-machines/2684-robins-smt-pick-place-build.html see post #7 for a converted engraving machine, it will give you some idea of speed vs mass and just how critical and precise the placement of the board and component strips need to be. Should also give you some ideas of what to look for on ebay.

A newer thread which may also be worth watching http://www.mycncuk.com/forums/other-cnc-machines/5369-jukus-pick-place-project.html

Also, for CNC type parts in the UK http://www.zappautomation.co.uk/en/ The owner, Garry, is a great guy, very helpful and, more importantly, very patient.

The plotter idea is not a bad one, it just depends on how much mass and/or resistance the pick-up head and attached vacuum tubing present vs the plotters mechanics. I have an old A3 plotter lying around and I suspect very little effort would be required to knock the mechanics out by a step or two.

Edit:
LOL, 8086 just found your MyCNCUk post. Good start

[8086]

I see the speed issue with the 3020...it's not going to be a very quick P&P So, that's out.

I figure I will try and make my own in that case. A plan is forming in my mind...

1. Belt driven, for speed, and low cost. Problem with accuracy though? I don't know...
2. Unsupported rails all round, no large forces to deal with and lower cost than supported rails.
3. Cam driven or belt driven Z-axis? Can't decide...
4. Maybe use extruded aluminium as a frame, not sure on fixings for rails etc though...
5. What motors to use? Belt direct drive so would need to be fairly high torque, simply for overcoming inertia on startup and reverse...

I figure I can get a fairly nice XYZ system for around £230 with this plan, unless there's anything I'm missing...

Thoughts would be appreciated And I will keep my log mostly here, simply for the fact that this forum seems more active than mycncuk. Oh, and the great minds I know reside here

[8086]

So, I mentioned my little project to my boss...and he donated to the cause

http://imgur.com/a/RiW32

Couldn't find the power supply, so had a bit of a faff about getting 9v and 31v in there, but got there in the end.

Going to see what my options are with it before I spend a load of money, though I'm only mildly hopeful that it's suitable for the job. We'll see...

[GeoffS]

You might have a loo at delta robots, they are fast!. Here's a commercial model showing off.
 

Quite a few of this style are being used as 3D printers so there's' quite a lot of DIY info available.