Computerless CNC Drilling

[grim]

Hello
I have been working on a project for some tim ethat is nearly complete. It uses a PCB and I have all the gear to make the boards (photo resist board, developing tanks etc)

The problem comes when I have to do the drilling. Pain in the backside....

Obviously I could spend a load of money on a full blown cnc drill. but there are a few points.

1. Cost.
2. not fun
3. I don't want to use a PC

My idea is for a drill that you teach. Insert a board, set the machine to learn mode and drill the holes i want, in the positions I want. then switch it over to run, and it will repeat those actions.

that can't be difficult can it?

I have a number of old printers which will donate stepper motors and some mechanics. lots of experimentation will follow.

I have only just started out, but I will try to keep this thread updated with my progress, maybe it will help others who know as little as I do!

Graham

[Ariox]

That would be nice, but you would need some sort of computer to record the actions taken on the drill, even if a much cheaper, specialised computer. But, recording the actions taken would be the hard part. Stepper motors are open ended; you don't get a confirmation of where you are. You'd need to create a system that could give feedback to your (ahem) "computer".

Then again, I don't know much, and I could be completely wrong.

[grim]

yes, it will need some computing power, and data storage, but i hope to achieve this with a PIC. I have the wish list pretty much sorted. I am currently using the machine in my imagination, thinking up neat features, that will be easier to design in, than try to add.

for example a DIL function so that you can tell the drill to follow the pin out of a DIL14 without having to manually enter the 14 holes, just the top left. saves programming time and memory.

A repeat function will be good, for when you have several identical circuits marked out on the same board. that should just need to use an offset function and away it will go. hopefully.

they are both just code functions though, so compared with the mechanics will be reasonably easy to include.

[skyten]

Even if you not use a PC you use electronic component, so you have to read the coordinates when you "learn" the positions to the equipment. If it not is more then an electronic position "jig" it must in a way know how to stop at the right locations with information from the "memory". To make the equipment to not need to go to 0,0 every time a translation of the 0,0 coordinates can be done from the last drill. I do not know if the deep of the drilling is to be recorded, in case not it is a two-dimensional system. Still think it is easier using a computer a used postscript device or plotter for finding locations, then you just draw it out in a cheap program using a pc or mac.

[grim]

ok, maybe I should rephrase my requirement. The machine will have limited on board processing power, rather than use an external PC. It will just be storing a list of locations, which a pic is quite capable of doing.

I don't want to dedicate my pc to the task. firstly, the pc is in the house and the machine will be in the shed. and i don't want to buy a seperate pc either.

the idea is for it to be cheap, and if i start of needing £300+ computer, then it won't be!

I admit that doing the first board by hand, rather than just dumping an image into a drilling prgram wil take longer, but the objective is to save me time making a quantity of boards, which it will do. i hope

[InspirationTool]

I'd stongly suggest keeping your ears open for an old used computer no-body wants and going traditional CNC with MACH3 or Turbocam. You can run both of them on a computer no-one will want anymore.

Much easier that what you are thinking about. Unless that PLC stuff sounds like fun.

-Jeff

[grim]

thanks for the advice, I am sure that a PC based CNC system running proper software would be better than my idea. but it's "my idea". Just something I want to try really.

also i will understand how it all works, rather than buying some bits that already work, bolting them together and ending up with something that works. that's not saying I will make it all myself. I am not going to wind my own motors or anything silly

it's also the challange of trying to achieve a lot, using a little. even the most basic pc has about a billion times the computing power needed for this project. i want to see how cheap and simple i can make it.

in years to come, i can see you all using this method!


(ok, maybe not) lol

[DareBee]

I am bewildered on the cost projection for this.
I can get an old PC for $50 or less.
A PLC, rack, IO cards and PS will cost me well over $200 for the oldest obsolete parts I can find.

I can forsee that you maybe have been donated some PLC equipped control panels for free, but don't forget the ladder logic program will cost you $ to be able to program the PLC.

That is not your point and I am sure you will have great time figuring the system out to suit your end needs.

[Ariox]

Originally Posted by grim ok, maybe I should rephrase my requirement. The machine will have limited on board processing power, rather than use an external PC. It will just be storing a list of locations, which a pic is quite capable of doing. I don't want to dedicate my pc to the task. firstly, the pc is in the house and the machine will be in the shed. and i don't want to buy a seperate pc either. the idea is for it to be cheap, and if i start of needing £300+ computer, then it won't be! I admit that doing the first board by hand, rather than just dumping an image into a drilling prgram wil take longer, but the objective is to save me time making a quantity of boards, which it will do. i hope

We have a bunch of older PCs in our garage that we picked up for free; they're not hard to come by. But, I do understand that you wanna try something new and see what you can do. People always give me funny looks too when I'm not doing things the "best" way.

But yes, I'm sure a PIC could handle the job, maybe the Basic stamp (parallax.com, I think), I know if you buy their development board things get really easy. Still, I don't know how you're going to get feedback from the machine.

[grim]

Originally Posted by DareBee I am bewildered on the cost projection for this. I can get an old PC for $50 or less. A PLC, rack, IO cards and PS will cost me well over $200 for the oldest obsolete parts I can find. I can forsee that you maybe have been donated some PLC equipped control panels for free, but don't forget the ladder logic program will cost you $ to be able to program the PLC. That is not your point and I am sure you will have great time figuring the system out to suit your end needs.

Yes, I can get computers for very little too. Actually I have three in my office awaiting breaking...... But then you have the bulk of the computers to lug around as well. Cheap will mean a CRT and that will mean heavy....

Also I wasn't planning on using a PLC or any IO cards. The pic will do it all, except the drive circuitry. (i'll admit now, that my experience with pics is pretty limited too, so that's more of a learning experience as well.....)

Your last sentance sums it up though it's the fun of designing it and making it, and then making it work.


thanks for all the replies. time to start hoarding more parts!

[dertsap]

Originally Posted by grim ok, maybe I should rephrase my requirement. The machine will have limited on board processing power, rather than use an external PC. It will just be storing a list of locations, which a pic is quite capable of doing. I don't want to dedicate my pc to the task. firstly, the pc is in the house and the machine will be in the shed. and i don't want to buy a seperate pc either. the idea is for it to be cheap, and if i start of needing £300+ computer, then it won't be! I admit that doing the first board by hand, rather than just dumping an image into a drilling prgram wil take longer, but the objective is to save me time making a quantity of boards, which it will do. i hope

thrift stores are full of dumpster pc's 20 buck your running

[grim]

ok ok ok

I could use a pc. BUT I DON'T WANT TO!!!!!


and breathe........




It's going to be a self contained unit, about 18" cubed, that will drill a few pcb's for me.

by the time i build it, i could have drilled the pcb already, but that's not the point.