My Build - I blame you lot for this....!

Today I finally got machine cutting after 2 months of design and building something that ended up nothing like what I was originally going to build, but that seems the norm! Don't know how much I have spent and don't really want to add it up otherwise it may put me off building another machine.

Totally enjoyed it from beginning to end (not that its complete yet), I got up this morning at 7.45am and was in the workshop at 7.50am with a cup of coffee adding the finishing touch's, at 9.30am I started it up and milled some writing on a piece of MDF with a big smile on my face. Something really rewarding about building a machine and seeing it work for the first time.

Spec -

All aluminium frame - tooling plate which I got at the right price!
80 x 40 Aluminium extrusion for bed length
THK 20mm linear slide all round - 4 bearings per axis
16mm Rolled ballscrews and nuts all round - courtesy of ZAPP.
3.1Nm stepper motors all round - Roy - DIYCNC
5A driver cards (Driver 50's) - Roy - DIYCNC
Uniport BOB - Roy - DIYCNC
36V power supply - Roy - DIYCNC
XLR connectors, stepper cable - Arc Eurotrade
Kress 1050 240v Spindle
Sideplate profiling - John S (nice job John)
Ballscrew machining - Me - On Leinen lathe I bought!
Motor and ball nut mounts - Me - again on lathe
Idea's and advice - you lot...


So I have attached some build pics which I have been taking while putting it together for you all to take the piss, point out the faults, tell me how nice it looks, etc etc.

There are 2 issue's I have with the machine at the moment and I am hoping for some sensible solutions please......

1 - The steppers run a bit notchy when at low speed, this may be normal but I am pretty new to all this, still seems to mill nice. Tried them on various microsteeping settings which did not make a difference and also Roy's advice from DIYCNC which made a slight improvement but I am still not 100% happy with them.

2 - Vibration on ballnuts when running between 1500 and 2700 mm per min, especially the 1m x axis. The nuts are lined up spot on with the screws to the point were I have been shimming them with shim steel to fine tune them. I can make the vibration go away by putting slight side force on the screw in any direction near the nut when running but did not think that was a solution. There is a very slight runout on the X axis screw in the centre and I mean very slight... bigger ballscrews, better quality or more grease???

The MDF bed is only temporary, I plan on making a T slot bed later on. Need to do a bit more testing and fine tuning first.

The large holes surrounded by the 4 smaller ones in the sideplates are for the built in 4th axis when I get round to it, that was John S's idea!

Not sure whether to build a smaller machine or a bigger one next, probably be a bigger one..!

A great job (one thing's for sure - I'm never gonna post up pictures of my scrapheap challege CNC rig after that!).

I can only add one small comment about your 'issue-ettes ....I can't see what type of couplers you're using (they're hidden), but what I established after using my little machine for a short while, is that the L050 'jaw couplers' I was using were very unforgiving wrt motor/rod misalignment (not saying your rods/motors are misaligned, and I can see you're saying they're not!)...I've since bought some Oldham couplers & wow, what a difference they make!

Anyway...great job - you've obviously thrown a lot of thought, effort (not to say dosh) at it!

Steve,
Problem 2, can you get any tension on the floating end of the ball screw and pull it to get some tension on it ?
I know you have double angular contacts at the drive end but if it's just floating over 1metre then it could be whipping,

Problem 1, Give me a bell over the weekend, I may have a fix.

.

Steve
A very nice job!
Ivan

Wow, looks great! Congratulations...

Putting me to shame Steve as i am still on the last base. Great job and at last you can play with your new toy.

Quote:

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Originally Posted by John S

Steve,
Problem 2, can you get any tension on the floating end of the ball screw and pull it to get some tension on it ?
I know you have double angular contacts at the drive end but if it's just floating over 1metre then it could be whipping,

Problem 1, Give me a bell over the weekend, I may have a fix.

.

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Problem 2 - Yes John, I could screwcut the ends of the ballscrews that are sticking out on the x and y as I left them a bit long and turned them down to 10mm, how much tension will it need as I only have a normal bearing in that end. I could always change it for a angular contact though (just 1). Running at 3100mm/min on rapid at moment and the vibration go's away when its warmed up, could it be that beacuse the gantry moves so easily that there is no load on the ballnut? I can feel a very small amount of backlash in the nut if i get hold of the gantry and pull and push on it, and I mean very small amount.

Problem 1 - Speak to you later.

Only if it works :clap:
Not all R&D sees the light of day.

Steve, battery on charge on the phone, try later.

Quote:

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Originally Posted by HankMcSpank

A great job (one thing's for sure - I'm never gonna post up pictures of my scrapheap challege CNC rig after that!).

I can only add one small comment about your 'issue-ettes ....I can't see what type of couplers you're using (they're hidden), but what I established after using my little machine for a short while, is that the L050 'jaw couplers' I was using were very unforgiving wrt motor/rod misalignment (not saying your rods/motors are misaligned, and I can see you're saying they're not!)...I've since bought some Oldham couplers & wow, what a difference they make!

Anyway...great job - you've obviously thrown a lot of thought, effort (not to say dosh) at it!

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Scrapheap challenge is one of my favourite programs, don't be ashamed and get some photo's up..!

As for the couplers, I am already using oldham's.

Quote:

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Originally Posted by Kip

Shiny bits :D 4th axis could be a limiter....depending on what you want to do with it.

Stick with the MDF bed.....5m rapids on the Z can get a bit giddy when setting up lol

I have some slatwall earmarked for mine.

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I thought you would like the shiny bits kipster..! lol

Quote:

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Originally Posted by Hemsworthlad

Steve how wide is your Z plate that router is mounted to?

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150mm - Check out the PDF attachment on my first post, most of the important dimensions are on there.

This was the minimum distance to allow for to thk bearings to fit end to end and also give me enough room to fit the nut and mount block behind.

Very nice job Steve :)

Just been playing with my new toy.

Just made this.....

Cycle time 7 mins
Cutter - Solid carbide 6mm dia 3 flute endmill
Spindle speed - No.2 on Kress router
Depth of cut - 2mm
Feedrate -800mm/min

Made a bit of noise and a lot of mess but i am quite impressed, just did it all in one pass, next time i will rough it and finish it then it should come out even nicer.

Yabut when Kip gets his free to a good home plasma working it will do the same thing in 5 seconds in hardened steel to 4 microns.

Alltogether now "We don't want no skeenking alloy"

:rofl:

.

Quote:

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Originally Posted by Hemsworthlad

Stop it Now. . .. . your teasing me on purpose.:nope:
Looks great to me just has is mate. . . . . If my machine cuts like that I,ll be well chuffed.

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Another pic below of the finished article, just had to finish it off..!

Quote:

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Originally Posted by Hemsworthlad

When we going to see a vid of it in action.

Kip take note, A "router" cutting the " Occasional bit of Ali ":rofl:

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Charging video camera now, will have vid posted tomorrow for you.

Hemsworthlad, do you have a spindle mount yet for that machine you are building??

Made it all myself, let me know what you want in it and I will see what I can do.

OK latest update...

Been trying to mill a 3D rooster from the Cut 3D demo program this afternoon and found a problem with my machine, after doing a finishing cut with a 3mm ballnose it returned to x0 y0 and was about 3-5mm out. I put it down to loosing steps and tried different settings in the motor tuning by changing the velocity and accel, made absolutely no difference at all.

Then I remebered that I had upped the kernal speed when trying 1/16th stepping so I dropped it down from 45k back to 25k and hey presto, no more lost steps, in fact the motors are running a lot smoother and the ballscrews vibration seems to have dissapeared.

Don't fully understand this so if someone could explain why the kernel speed was so critical I would be interested to know.

I am ruuning mach on an old compaq P3 866mhz machine but in the driver setup program it said it was running 'excellent' at 45k.

You must be nuts to run at that kernal speed.

.

Quote:

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Originally Posted by John S

You must be nuts to run at that kernal speed.

.

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Had to up the kernal speed because it was limiting the max speed of the motors. At 1/16th microstepping I was set at 3200 steps per mm which meant the max i could get the velocity to was about 460mm / min.

Oh sod it, forget it that joke was obviously wasted ......................

Light bulb just came on.... :biggrin:

Is this about routing or rooting????....both sound good anyway lmao

Quote:

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Originally Posted by HiltonSteve

The large holes surrounded by the 4 smaller ones in the sideplates are for the built in 4th axis when I get round to it, that was John S's idea!

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I was just about to ask !

Ok, here's the video for you. Its a bit noisy so be warned.

DIY CNC Router cutting MYCNCUK logo in MDF
http://www.youtube.com/watch?v=1oL4Du3OmBs

I am Soooooooooooooooooooooooooooooooooooo jealous :toot::clap::clap::clap::clap::clap:

Great video Steve and congrats on the machine,what did you use to generate the g code?

Andy

Quote:

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Originally Posted by audioandy

Great video Steve and congrats on the machine,what did you use to generate the g code?

Andy

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ArtCam pro.

Took me a few hours to get to grips with it but once you get the hang of it you can do anything you want. You can download a trial version from the website if you want to have a play.

http://www.artcam.com/downloads/broc...brochures.html

OK, will sort it tonight.

Never mind routers cutting ali, considering making a slower high torque spindle and fitting a coolant pump so that I can cut steel. I think it should be possible with small carbide endmills but we will see.......

Quick query Steve - when you said in the OP "All aluminium frame - tooling plate which I got at the right price!" any chance you could let on where that was from?

See John S is recommending ASC Metals in another thread. Thought might also be worth trying Metalfast's offcuts service but apart from those any ideas?

Quote:

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Originally Posted by bikepete

Quick query Steve - when you said in the OP "All aluminium frame - tooling plate which I got at the right price!" any chance you could let on where that was from?

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Leengate Metals in Nottingham - http://www.leengatemetals.co.uk/

I got all my aluminium tooling plate for the same price as standard plate as they had just bought a load from a company that went bang. Don't know if they have any left but I would have thought so.

Quote:

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Originally Posted by Kip

Try service metals...They just quoted me happy on a piece of 800x420x30mm plate....Just crept into 3 figures!

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Thats a good price.....

Photo of same logo in aluminium.....

3mm cutter
600mm/min

took about 10 mins.

I think I could seriously speed it up by taking less material in one cut and up the feedrates, going to have another go now...

Dunno what the problem is cutting metal on a router ?

I bought my little Isel for small metal jobs and engraving.

http://www.stevenson-engineers.co.uk...llanfairpg.jpg

Done as a demo but look at the tails of the g's, every one is perfect and finishes up as a feather edge.

Any lost steps, loose screws etc would have meant that it lacked consistency.

.

Nice job john, what cutters did you use for that??

Just had another go at the MYCNCUK logo with different method -

3mm coated carbide cutter running at between no.3 and no.4 on the kress.
Finish depth 3mm both times.

1st time -
Rough it out with 1.5mm depth of cut @ 600mm/min leaving 0.5mm on the sides then finish it at same speed. Time taken - 10mins

2nd time -
Rough it out with 1mm depth of cut @ 1000mm/min, fancy ramping moves instead of plunging, leaving 0.3 in the bottom and 0.5 on the sides, finish cut at the same speed. Time taken - 11 mins

Problem is cutter keeps getting clogged up, did not stop it just tried to dodge the large clogged up bits coming off the cutter now and again.

Will be buying some proper cutters for aluminium tomorrow, see if thats any better.

Try LanfairPG :rofl:

Steve,
The problem is recutting chips, the less flutes the better as it's not the cutting action that's the problem, it's the space for the chips to go.
A single flute router cutter works best in alloy unless you buy special cutters.

Even then you need coolant, well more lubricant to be precise to stop the welding to the tool.

WD40 is advise for aleoy and it works well but being tight I make my own, 75% paraffin and 25% ATF or any light hydraulic oil.

Modify an oild spray gun to give you plenty of air but just a dribble of knacker laqueur.

.

Quote:

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Originally Posted by HiltonSteve

Problem is cutter keeps getting clogged up

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I can’t find the link now but I did read on a wiki page awhile ago that this because the cutter is cutting/braking the chips up to fast and that the flutes can't remove them from the job quick enough.

I also tested this when I had my Rockcliff running, I started off with a speed that was ok and seemed to work, I then turned the speed up on the router and that’s when everything went a wee bit Pete Tong!

Sure enough the cutter started to clog and then started to jam in the Ali, the end result was this:

Click the image for a bigger view !

http://www.mycncuk.com/forums/photop...1_DSC06356.JPG

Now it may have pushed on but I was using some spring clamps to hold the Ali down and as soon as the jamming started the Ali plate started to move and the E-Stop was the call of the day.

I have looked for the "right" speeds for different size cutters but everyone seems to run different to the next man. I think you basically have to work out what works for you in different materials and then log the data for next time you want to do the same kind of job.

Lee

John replyed as i was typing my reply out.

Learn to type faster.:nope:
.

Been playing with my machine again trying to get aluminium to cut nice and...

John, you were right. (No suprise there then! :wink:)

Tried a few different methods of profiling some 2mm aluminium sheet and came to the conclusion that slower is better with these 3 flute cutters that I have.

After various speeds and welding some ali to a 3mm cutter (is there an easy way to get it off without breaking the tool??) I ended up with the kress set on 1 and cutting at 100mm/min with a full 2mm cut straight through the plate, started chipping lovely, gave it a squirt of wd40 and vacuumed the chips up now and again.

I believe that any reasonably built router will be capable of cutting ali with the right speeds and feeds as the cutting forces are very low.

I think I will be able to go a bit quicker with the 2 flute ali master cutters that I have ordered but I will let you know tomorrow.

So here is a photo of my new Z axis sideplate.....:smile: