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

[HiltonSteve]

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..!

[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!

[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.

.

[Kn8]

Steve
A very nice job!
Ivan

[bikepete]

Wow, looks great! Congratulations...

[Swarfing]

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.

[HiltonSteve]

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.

.

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.

[John S]

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

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

[HiltonSteve]

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!

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.

[HiltonSteve]

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.

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