105 replies to this topic

[jonas]

What's the position exactitude of the cnc
There are some crazy inventors around here
Well done!

[spiyda]

I think its a mill converted to cnc, and then a multitool bolted to the side,
Im saving for a hobby mill then eventually ill convert it to CNC.
but then i also want a new welder so im just saving the pennies now.

yep,

it's an Seig X1 clone from Axminster tools.
The CNC conversion was done with odd bits I had lying around + skate bearings.
The stepper motors are run from Mach3 through a ready made driver running off an old PC power supply.
The chuck on the side is the old one off my lathe mounted on an old worm drive gearbox I had in the shed !
when it's adjusted, the backlash is less than 0.005mm and the theorectical resolution about 0.0025mm
The resolution on the side chuck is approx 0.09 degrees, but I need to make it finer.

The first job it did was drilling the pcbs for the mini brake lights. Ideal because the same part is done hundreds of times.
The machining on the inlet manifold for the Minuki was dome on it, matching the oval portts was easy.

The accuracy of the machined piece depends a lot on how fine a cut is made, as being only a light machine, it can flex with bigger cuts.

What sort of welder are you going for ? I have arc, mig and spot, my next will be a tig (need more pennies though !)



Chris

Edited by spiyda, 22 January 2008 - 09:40 PM.

[Shifty]

i think i have seen one like that before

An ex work collegue built a swift engined mini a few years back, from memory it was metallic blue(ford colour) with a silver roof. The rocker cover was poss painted with a jap rising sun picture.

Its reg was b***con from memory

Was this the one?

[spiyda]

I wouldnt stick the servo on just 1 cylinder, but connect all with a larger tube then its equal across the cylinders.
you should only need one non-return valve in the pipe to the servo, and having a large pipe between all inlets will help balance them (of not completely).

If you already have a V3 its not hard to add the flyback circuit, but the resistors should work to. I think the difference is PWM adds more control and better response for the injectors.

I know what you mean with the Bini charger, so much so that one came in the post last week

Ed

re vacuum...Cool, thats what we'll do then,
re injectors, the resistors will be the first attempt, less work to get it to start up.. if we have problems, we can add the flyback.

C

[ed4ran]

yeah that mill is along the lines i was looking at,
welder wise i was thinking TIG,
I recon i could get one of them next month, but dont know which, or i might just wait a bit longer.

Are you going to get more accurate motors for the cnc, or is there a scale option on the controller?

Ed

[spiyda]

Are you going to get more accurate motors for the cnc, or is there a scale option on the controller?

Ed

It just needs a 4:1 pair of pulleys and a toothed belt.

The ratios at the moment are fine for the driveshaft splines.

C

[ed4ran]

cool, guess you then need to scale up the program/model? or do you tell it what ratio you are using anyway?

[spiyda]

cool, guess you then need to scale up the program/model? or do you tell it what ratio you are using anyway?

OK Ed, you did ask !!!!

Mach3 has a configuration wizard that allows you to enter how many steps per unit (mm or inch) your particular setup has..
For the rotary axis, I treated as a flat plane, I think I set it up on mine to be 100mm high (so the numbers are easy to calculate, it could just as easily be 360 to make it easy to work in degrees), the setting in the configuration is how many steps the motor has to move to move 1mm

The 100mm is an arbitary number, but it means if I tell the axis to move 5mm it actually rotates 5/100 of a turn, or in other words it takes 20 lots of 5mm to make a complete turn... hence I get 20 splines !

the 'g'code for the splines is then just a series of horizontal lines.. eg.

G0 Y0 (in to touch driveshaft )
G1 Y0.1 (take 0.1 cut)
G1 X45 (cut right to right end of spline)
G0 Y-5 (move tool out from shaft)
G1 A5 (rotate shaft for next spline)
G0 X0 (moves to far left of spline)

G0 Y0 (in to touch driveshaft )
G1 Y0.1 (take 0.1 cut)
G1 X45 (cut right to right end of spline)
G0 Y-5 (move tool out from shaft)
G1 A10 (rotate shaft for next spline)
G0 X0 (moves to far left of spline)

(only much much more of them to do a complete shaft.. it takes about 7 cuts to go full depth on each spline)

where
Y moves the cutter in and out of the metal
X is left and right along the driveshaft
A is the rotary motion

Z is up and down on the cutter and not used in the spline program.

If you decide to build a machine, come over and see us when Pete is here... and I'll show you in more detail
(because tyhis is probably boring to most of the forum readers)

Chris

[ed4ran]

Yeah thought it was going to be something like that.

I may very well do that Just need to decide on which machine and which cnc kit to use, although i might buy the machine first then look for a suitable kit.

[spiyda]

Yeah thought it was going to be something like that.

I may very well do that Just need to decide on which machine and which cnc kit to use, although i might buy the machine first then look for a suitable kit.

If you want to skim heads etc, you will need a bigger machine, the X1 doesn't have sufficient x-y travel

but I wouldn't buy a kit, just buy the driver board, and use the machine to make the other parts.

I am sorely tempted by this board, (ebay Item number: 330206231796) it is much better than the one I have.

I guess we'd better take this offline..

C

[Jammy]

Ooo, me interested too! But I'm new too all this (well, I understand the code and how you program it, but the bits and pieces used is new to me). Where abouts are you?

[ed4ran]

Yeah ive been looking at the different boards and motors on ebay, as well as the different mills, have thought of which to get yet.
Have also been looking at cnc routers, but they are limited on materials they can cut (i have seen alu and sheet steel, but they have to go slowly)

Didn't really plan on things like head skimming, more flanges and smaller machining work, at least to begin with

I only think it needs taking offline if pete doesnt want it cluttering his project page, possibly start a new thread to talk about it.

Ed.

[spiyda]

Yeah ive been looking at the different boards and motors on ebay, as well as the different mills, have thought of which to get yet.
Have also been looking at cnc routers, but they are limited on materials they can cut (i have seen alu and sheet steel, but they have to go slowly)

Didn't really plan on things like head skimming, more flanges and smaller machining work, at least to begin with

I only think it needs taking offline if pete doesnt want it cluttering his project page, possibly start a new thread to talk about it.

Ed.

I don't profess to be an expert, but the board I mentioned earlier seems to be a good buy.
as for motors, its worth getting nema 23's bigger than mine, however, linking them to the leadscrews with a toothed belt solves a lot of alignment problems.

You should come over and visit and take a look at the machine while Pete is here..

and maybe give us some ideas on finishing the build )

Chris

[Joshmini]

Get a pair of nice 13x7 deep dish wheels!
looking nice engine, how much BHP it give off?

[clubby]

SURE like mcgyver