Starting point for a pick and place - cheapy CNC and convert or build my own?

[8086]

Hi all,

I'm a member over at eevblog.com forums and there was some discussion about homebrew pick and place machines, when I asked about a cheapy cnc frame/xy gantry kit this forum was mentioned, so here I am!

What I need is a simple x/y system with fully moveable axes - i.e. the system can't be based on a moving work piece, as the components to be picked won't be able to move with it. The whole assembly needs to be able to reach the components location(along one or more sides of the machine). I hope that makes sense. My budget for at least an X/Y system is about £300. With added things like motors I will extend the budget but for just the X/Y I don't want to spend too much.

So I was looking at either this system I found on ebay: NEW 3020 DESKTOP ROUTER ENGRAVER DRILLING/MILLING ENGRAVING MACHINE CNC h3 | eBay

or making my own system from scratch. I would prefer to start from scratch, in a way, but I don't really have any metalworking tools. So I would need to have the pieces made after I designed them. So, three questions for you lovely people:

1. Buy and hack, or build from scratch, bearing in mind my lack of tools?
2. If buy and hack, what do you think of the ebay item above? What sort of accuracy would I be expecting from such a machine?
3. If build from scratch, are there many companies that will cnc some metal parts from say, gerber files I have created?

Cheers!

[martin54]

I'm pretty new to this forum myself so maybe not best placed to advise but if it were me then I would be looking to build from scratch rather than buy an off the shelf machine & then start hacking it about trying to make it suit your requirements.
If you start from scratch you can built the machine to the exact specification you require for your project. Don't know what your aim is but you may find that most parts from the off the shelf machine are not suitable for your need which is then just a waste of money.
It all depends on what you want the machine to do, pick & place could mean almost anything lol.

Even with a limited supply of tools it is possible to construct a machine with a bit of help, even if you bought an off the shelf machine you would have the same problem trying to modify it.

There are plenty of people about who would be able to machine parts for you from what I have seen so far, when you say Gerber files are you using something like Omega? If so as long as you can export as a DXF, EPS or ai vector file which you should be able to do then someone will be able to help.

[JuKu]

The ebay item looks nice. You might also want to check out Shapeoko, Shapeoko | Precision by DefaultShapeoko | Precision by Default and the forum there, as well as eShapeoko MakerSlide Europe - MakerSlide Europe - (Powered by CubeCart). I don't think you can do without machining at least some custom parts, but you can design a machine so, that you only need to cut sheet metal. Cutting and drilling aluminum might be doable for you? Even if not, sheet metal parts should not be very expensive from a laser cutter shop. Gerber is not a good file format, but there are some free or cheap mechanical CAD programs.

[8086]

I'm pretty new to this forum myself so maybe not best placed to advise but if it were me then I would be looking to build from scratch rather than buy an off the shelf machine & then start hacking it about trying to make it suit your requirements.

You are probably right. I will need to build my own if I want to get the combo of speed/cost I want.

If you start from scratch you can built the machine to the exact specification you require for your project. Don't know what your aim is but you may find that most parts from the off the shelf machine are not suitable for your need which is then just a waste of money.
It all depends on what you want the machine to do, pick & place could mean almost anything lol.

Well, I want it to pick and place electronic parts. Similar to this: DIY SMT IMPROVISED PICK AND PLACE MACHINE (TEST) - EMC LINUX - YouTube
I am hoping to make mine faster though.

Even with a limited supply of tools it is possible to construct a machine with a bit of help, even if you bought an off the shelf machine you would have the same problem trying to modify it.

True.

There are plenty of people about who would be able to machine parts for you from what I have seen so far, when you say Gerber files are you using something like Omega? If so as long as you can export as a DXF, EPS or ai vector file which you should be able to do then someone will be able to help.

Well I say gerbers because as my day job is a PCB designer I am used to the format - the parts I would need to have machined would all essentially be 2-dimensional (excluding the thickness of the material). i.e. an outline and holes, much like a PCB. I would be using Altium Designer if I used gerbers. I think it has a DXF export option, actually. I will have to look tomorrow.

The ebay item looks nice. You might also want to check out Shapeoko, Shapeoko | Precision by DefaultShapeoko | Precision by Default and the forum there, as well as eShapeoko MakerSlide Europe - MakerSlide Europe - (Powered by CubeCart). I don't think you can do without machining at least some custom parts, but you can design a machine so, that you only need to cut sheet metal. Cutting and drilling aluminum might be doable for you? Even if not, sheet metal parts should not be very expensive from a laser cutter shop. Gerber is not a good file format, but there are some free or cheap mechanical CAD programs.

Shapeoko I looked at, but it seems to simpe in construction, so simple I may as well try myself to build one.

Do you know any good laser cutting or machining shops that I could use to make custom parts I may need?

So, a few thoughts...

1. Should I make it 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...


Thanks guys

[JuKu]

My take on your list:
1: I'm going for belt. My goal is better and faster than hand placement, and belt (GT2) is more than enough for that.
2: Agreed.
3: Cam, just because Zapp has a nice motor for that: SY17STH0404-200TR8X8-EX
4: I'll have extrusions bolted on table along X, Y shafts mounted on these, tapes coming in under the Y shafts.
5: At least as important is the driving algorithm. I think I'll use TinyG driver board (https://www.synthetos.com/webstore/i...cs/tiny-g.html). It has 3rd order acceleration, and allows customization of the software (I know how to program Atmel micros). TinyG and Nema17 motors are fast enough for me: https://www.youtube.com/watch?v=Om0w...feature=relmfu

[8086]

My take on your list:
1: I'm going for belt. My goal is better and faster than hand placement, and belt (GT2) is more than enough for that.
2: Agreed.
3: Cam, just because Zapp has a nice motor for that: SY17STH0404-200TR8X8-EX
4: I'll have extrusions bolted on table along X, Y shafts mounted on these, tapes coming in under the Y shafts.
5: At least as important is the driving algorithm. I think I'll use TinyG driver board (https://www.synthetos.com/webstore/i...cs/tiny-g.html). It has 3rd order acceleration, and allows customization of the software (I know how to program Atmel micros). TinyG and Nema17 motors are fast enough for me: https://www.youtube.com/watch?v=Om0w...feature=relmfu

Okay, so belt is good, and so are unsupported rails. Great

Still not entirely sold on the cam idea, it seems...inflexible.

The alu extrusions, have you found any systems that 'mate' nicely? I can't get an easy combo of extrusion/rail supports, etc. Is it always simply a case of having to drill it yourself to accommodate the rails? Ideally, I want to have minimal machining, since a) I can't do it very accurately with what I have, and b) using the extrusions slot features allows some flexibility in future.

I think I will end up making my own driver board, but it's good to see nema17 is sufficient. I suppose 24V is the best voltage for them?

[martin54]

Few people on here use ally profile & there are a number of different systems about. as for fitting the rail supports then yes people would drill & tap themselves but it's not difficult if you take your time & use clamps rather than try & hold stuff by hand.
Have a look at this thread, very interesting I thought but then I know nothing about pick & place machines lol. Might give you some ideas for your own design.

http://www.mycncuk.com/forums/other-...ace-build.html

I would take a bit of time & make sure you get the design sorted before you start to purchase anything as builds have a habit of changing a lot from the original plans.

[8086]

Oh, I am going to have some fun planning for a while yet before I buy stuff ;)

I wonder if a wood construction would be sufficient, at least for the first go? I could modify it more easily than metal. I just am not sure about the strength and rigidity.

Are there places that will laser cut, say, 20mm MDF to spec?

[8086]

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

Roland Plotter - Imgur

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...

[Robin Hewitt]

Roland Plotter - Imgur

I've got one of them. I tend to collect things I used to drool over. Things I could not afford can now be picked up for a few quid.
I wonder if you could gut a steel tipped pen and convert it to a pick up nozzle?