Guitar Neck and Z axis issues

[jb2060]

Hi All,

Well I took my first deep dive into 3D CNC today when I ran a guitar neck job through its paces. Overall I was quite pleased with the results but the job highlighted a serious issue I have with my Z axis dropping steps. I have known about the Z axis issue since I first got the driver box but it took 3D carving to really amplify the issue.

Although I will continue to hand shape my necks, this will be a way for me to replicate necks I have hand carved, for future builds. I will do this by digitising them with my recently acquired digitiser :-)

I am going to have to bite the bullet and get a new driver box (Rod: you knew this time would come :D).

Greg: I saw your recent post which recommended the Gecko540. I had a quick look and it looks very good. It looks like I would just need a power supply and I would be away. Am I oversimplifying this? The other option I would consider is the Xylotex.

Here are some pics of the Roughing ToolPath and the Finishing tool path

[rodm]

Hi Jason,
Fantastic work. :2tsup:
I would like to know more about the 3D process you are using, Are you doing your own drawings and if so what software?
Yeah the Z axis was suspect right from day one so good to hear you are doing something about it.
I ran a 3D job today but it was purchased vector art and no where as exciting as you have done here.
I'll leave it to Greg to offer advice on the drivers - the 504 does look like a good package to me. Higher input voltage and mid band resonance compensation will smooth the motors for you. The Xylotex are not in the same league as Gecko but they are a good driver for half the price.

[jb2060]

Hi Rod,

Thanks for your kind words.

I am using a trial version of Rhino3D (25 saves) which I have found to be an excellent application. Being frugal on the saves makes it a bit tense after a couple of hours work without a save. I have been learning Rhino for a couple of months and was able to get good enough to pump out a fairly basic neck design. It is a very steep learning curve though and a real challenge to think and act in 3D. After I draw it in Rhino I use Cut3D to generate the toolpaths - that took a bit of time to get right also:roll:. It then went to the machine (using Mach3 of course).

Rhino is pretty well priced if you use it a lot but I am not sure yet if I can justify the purchase yet. Will have to think that one over a bit. I have also had a look at MOI (moment of Inspiration) for 3D CAD which is good but nowhere near Rhino - a lot cheaper though.

[appiwood]

Hello Jason,

I have used my belt / screw driven machine to cut nosecone plugs for R/C aircraft, the biggest was almost 1200mm long ( the nosecone not the aircraft ) and was having problems with the Z axis missing steps, ( the Z drive is a ballscrew ) what it turned out to be was a small amount of movement in the angular bearing holder, once that was secured the problem went away.

Your Z looks fairly light, is your axis stiff or tight? could you fis the problem with a bigger stepper? what size are you using?

Are you sure your cut file is OK? the Rhino file I used ( was supplied by a mate ) had some funny joins, if you would like I am happy to cut one on mine, I am running Cut3D to.
If you are interested PM me.

Ed

[Greolt]

G'day Jason

Yeah 3D work will show up a Z axis weakness for sure. On 2D we tend to have slower Z movements because we often set our tool to plunge slower than cut.

Typically it will slowly get lower as the job progresses. Everything works a little harder to change direction at the bottom compared to the top.

The G540 is certainly a superior drive to Xylotex and it's peers. However it won't cover over other weaknesses.

What is your current drive, power supply, motor setup? What lead screw? Are there obvious mechanical improvements that can be made?

Sometimes just slowing down the Z rapid speed or acceleration in motor tuning can make sufficient difference.

Greg

[rodm]

Hi Greg,
Jason and I went through all the troubleshooting quite a while ago and proved that the driver board was the problem. It was a custom made board and the fault was evident from day one. Shift another axis to the same motor port on the driver board and the problem goes with the new axis.
It has been sort of OK until now because there is less Z movment on 2D jobs.
Yes he could salvage the toroidal power supply out of the box but it is 24 volt and from my understanding 36 volt would be better. My thinking is if he wants to remove the problem then now is the time to do it. A 36 volt switching power supply is quite cheap over ebay.
Your thoughts?

[Greolt]

Rod and Jason

Aaaah well if you are sure that the drive is your problem then I would see the G540 as a good way to go. Very likely your motors are 3amp. So they would be a good fit.

G540 is capable of 50v. If you have an existing linear supply then I would just replace the toroidal transformer with a larger one.
Maybe 30v (42v DC) Highly likely the rectifier and capacitor would still be within spec. Simple mod.

Since you asked, I am definitely no fan of those cheap Chinese switch mode supplies for a cnc machine. I have seen too many fail.
Sometimes giving confusing symptoms. Other times just going BANG! Others mileage may vary. :) That is my experience and my opinion.

Now having said all that if your machine is overall doing what you want apart from this drive issue then a Xylotex would be a viable drop in fix.
(I have an almost brand new four axis one you can have cheap) :D

Greg

[jb2060]

Hi Ed,
Thanks for the offer but the rhino file is ok. The Z axis is also very smooth with no backlash - The motors also perform very well on the other axis. I would be very interested in having a look at some of the CNC work you have done. thanks, Jason

Hi Greg,

Thanks for that: Rod is quite right. I currently have the Z running off the X driver because accurate X and Y are more important for most of the cuts I do. I ran extensive tests before confirming that the driver board was the issue. The problem was exactly the same on X before I switched plugs to the Z motor. X then ran perfectly and Z had the problem.

I would be very interested on your views about power supply etc.

[jb2060]

Hi Greg, I posted as you were replying. sorry 'bout that:U

The steppers are Compumotor LN57-83 100oz/in 2.2amp(I think).

I would prefer to build a totally new driver box based around the G540. I will keep the other as a 2.5D backup. I'm off to the US on Thursday for a week so I will see if I can get one while I am there. Do you have a recommendation on a supplier to get the other parts I need (power supply, fan etc) ?...I may as well save on the postage while I am there. :D

[Greolt]

Jason

Those little 100oz motors fall within the Xylotex 2.5 amp max. What voltage are you currently feeding them? I could not find any specs on them.

I think there is currently a supply issue with the G540. May not be available until you are back home.

If your current setup is 30v or below maybe the Xylotex is the simplest way to get it going.

If you can easily mount it in your control box and allow a little cooling fan to blow over it, that might be easiest.

How is your basic electronics skills? Can you solder, read a multi meter, logically follow basic wiring? Sorry to ask. :)

Greg

EDIT; Are those drives bipolar or unipolar? How many wires do the motors have coming out of them? And how many connect to the drivers?

[jb2060]

Hi Greg,

Here is the wiring diagram for the motors. They are series and 8 wire - 4 wires connect to the drives. I have attached the manual that the guy in singapore gave me (I couldn't find the Bipolar/unipolar reference).

I can solder, read a multi meter and logically follow basic wiring (but I am also prone to asking dumb questions when I have overestimated my ability:U)

I saw the leadtimes on the G540 too and thought I might call and beg as I am only there for the week (can't hurt to ask). I hear you on the motors - might be time to upgrade them too - they have not missed a beat though and have performed very well, especially for their low torque. Rod has been at me too, about the motors:D. If I have some more steppers and a backup driver box it might encourage me to build another machine:2tsup:

[Greolt]

The present motors are doing the job............but if you have your heart set on some new motors I can certainly relate to that. :B

These would be a good match to the G540 or even the Xylotex.

KL23H276-28-4B (1/4" Dual Shaft with flat ) Price: $39

http://www.kelinginc.net/NEMA23Motor.html

With the G540 you could go for 42 to 48v power supply

As I have said I am no fan of switching supplies but if for ease of setup you wanted to go that way then Kelling also has them,

http://www.kelinginc.net/SwitchingPowerSupply.html

5 amp one would probably be fine but for an extra $10 you could get a 7.3 amp

If you wanted to build a linear supply you only need a few components,

One of these,

http://www.altronics.com.au/index.asp?area=item&id=M5530

and one of these,

http://www.altronics.com.au/index.asp?area=item&id=Z0091

and a capacitor which I can supply for you.

Greg

[appiwood]

Hello Jason

One other thing I thought of that won't help you much if you change the drive / motor is, to speed up the cut rather than having the Y axis as your primary move make the X the primary move, if you run the tool up, over and down the neck rather than up a little while the cutter is running along the length of the neck it will go much quicker, you can tell Cut3D to do that and it will mean less starting and stopping for the Z, try it in C3D and see the difference.

Good luck with your new drives.

Ed

BTW, if you are brinning in stuff from several sources contact Elwood Beauchamp at [email protected] ([email protected]) have the items sent to him and he will re-pack into a 20Lb box and air mail it over, a 20Lb box costs ( from memory ) US$38.00 to sens and he charges US$15.00, I have used him on numerous occasions and the box gets here fast ( about 5-7 days ) and without trouble.

[jb2060]

Hi Ed,

Thanks for that. I did try running along X then Y after the first finishing toolpath didn't turn out well - it was just dropping too many steps for Cut3D to come to the rescue. I will keep the shipping contact in mind for the future..thanks

[jb2060]

Hi Greg,

I am back from the US and couldn't get the Gecko 540 organised in the short timeframe. I am going back again in at the end of next week so I might be able to line up the 8 day leadtime. Failing that I will just get it shipped international.

I PM'ed you before I left (below) to see if you were interested in selling me the Xylotex that you are not using (I think your inbox is full because it didn't go through). This could get me by in the iterim and then serve as a backup driver box when I install the G540. Like I mentioned below - I am more than ok if you want to hold onto it.

thanks again, Jason

[jb2060]

The present motors are doing the job............but if you have your heart set on some new motors I can certainly relate to that. :B

These would be a good match to the G540 or even the Xylotex.

KL23H276-28-4B (1/4" Dual Shaft with flat ) Price: $39

http://www.kelinginc.net/NEMA23Motor.html

With the G540 you could go for 42 to 48v power supply

As I have said I am no fan of switching supplies but if for ease of setup you wanted to go that way then Kelling also has them,

http://www.kelinginc.net/SwitchingPowerSupply.html

5 amp one would probably be fine but for an extra $10 you could get a 7.3 amp

If you wanted to build a linear supply you only need a few components,

One of these,

http://www.altronics.com.au/index.asp?area=item&id=M5530

and one of these,

http://www.altronics.com.au/index.asp?area=item&id=Z0091

and a capacitor which I can supply for you.

Greg

Hi Greg, My very belated reply to Post#12. Sorry -- not sure what happened there.

I will certainly take your advice on the G540 and those steppers look very good too. I don't really know the difference between Switching and Linear power supplies but I am happy to take your word that Linear is better. I looked at the dimensions of the G540 and it is quite small (15 cm wide). I will have a look around for a suitable box to house it (and the power supply).

I was very impressed with the speed of your 3D carve (recent post). I am going to have a look around for some 1/4 and 1/8 ball end mills (i will hopefully will find some long shafted ones too).

thanks again.

[jb2060]

Hi Greg,

As a follow up to the last post: is there a sweet spot for the voltage/torque/speed combination. I really want to get my machine humming (to handle the 3D stuff) and I would rather pay a few dollars more to get the right mix of componants.

I recognise that new motors will make a difference (no smirking Rod:rolleyes:) but should I push into 382oz/in or does that sacrifice some speed? Also does moving to a 48V power supply give me advantages or is it best to just match to Drives and motors?

If it is a factor: Of the material I cut, rock maple and ebony are the hardest. I do want to give aluminium a go too.

Also with You, Rod and Sean going with spindles: It definitely want to get one (noise being the major motivation).

[Greolt]

Jason

Looking at what you have and how it has all been working I think that 270oz motors would be a good match.

This part No. from Kelling KL23H276-28-4B This is a dual shaft 270oz bipolar 2.8 amp

For now stick with the 24 volt power supply. Fit the Xylotex in place of present driver (you should have it on Monday) 24v is a good size for it.

You will be very pleased with the improvement in your machine. That is what I would do.

If you want to get a G540 then a larger power supply would be desirable. 48v would be a good match for it. The 270oz motors would still be a good match.

But if you really wanted to then Kelling KL23H2100-30-4B would be the next up.

Looking at the pic of your current setup I can not tell if the extra windings on the toroidal are added to the secondary or are a separate winding to provide fan power.

Looks a bit sus but that is probably just because I can't see in the flesh. :)

It would be good if you could rearrange things to get the fan blowing on the Xylotex heatsinks.

Greg

[jb2060]

Jason

Looking at what you have and how it has all been working I think that 270oz motors would be a good match.

This part No. from Kelling KL23H276-28-4B This is a dual shaft 270oz bipolar 2.8 amp

For now stick with the 24 volt power supply. Fit the Xylotex in place of present driver (you should have it on Monday) 24v is a good size for it.

You will be very pleased with the improvement in your machine. That is what I would do.

If you want to get a G540 then a larger power supply would be desirable. 48v would be a good match for it. The 270oz motors would still be a good match.

But if you really wanted to then Kelling KL23H2100-30-4B would be the next up.

Looking at the pic of your current setup I can not tell if the extra windings on the toroidal are added to the secondary or are a separate winding to provide fan power.

Looks a bit sus but that is probably just because I can't see in the flesh. :)

It would be good if you could rearrange things to get the fan blowing on the Xylotex heatsinks.

Greg

thanks Greg,

There are 2 wires going from the tordial to the rectifier and 2 wires going to the power cord - no other wires from the tordial. The fan is only connected to the driver board. The other 2 red wires exiting the side of the box are for my touchplate 'alaGreolt'. If the Xylotex works a treat I will hold off on the G540 for a little while. The motors are a must, though.

[crocky]

Jason

It would be good if you could rearrange things to get the fan blowing on the Xylotex heatsinks.

Definitely get the fan to blow over the xylotex heat sinks even if it means installing another fan just for them. They are good items but you must cool them properly.

[jb2060]

Well thanks to Greg because the Xylotex Driver board worked a treat. I have just plugged it all together (after triple checking my wiring) and it worked - I have just been running some tests and I just have to change the direction of Y axis (which I had to do with the old driver too). I will also have to get a 24V fan tomorrow because the old one is 12V.

I noticed straight away that the Z axis sounds different when jogging.

I have ordered my 4 Keling Steppers (KL23H276-28-4B) so they might be here early next week. When I install these I will push the limits of my newly configured machine and see how it stacks up to the old version.

[Greolt]

Glad it is all happening Jason.

Reverse the axis go to menu Config -/- Homing/Limits -/- tick reversed

Greg

[crocky]

Looks good :)

[jb2060]

Greg/Rod,

I noticed that Rod's Instructions (a few months back) for his 3 Axis Xylotex that PIN15 and Ground were used for the touch plate (with the resistor too). Can I just use any spare PIN on the 4 Axis board (and Ground) for the touch plate set up?

I have also realised that the existing fan in my driver box is 12V and I can't find a 12V output from the Xylotex. The power supply is 24V (reads 25.4V on the multimeter). I couldn't find a 24V fan at Dick Smiths or Jaycar today unfortunately. Is it possible to run the 12V fan off the 24V Power supply, through the Xylotex? Will it just run twice as fast? It's scary how much I don't know about electronics:B

[Greolt]

Jason

Only pins 10 11 12 13 and 15 are inputs. Any of those should be fine.

Re hooking it up I will leave that for Rod as I have never done it straight to the LPT.

Rod has hooked a few of them up. I have always done it through a BoB or a SmoothStepper.

With the fan, I have the same situation and run two 12v fans in series.

I think you could run a resistor in series with it, matched so it sees 12v.

That is probably a bit agricultural. I'm only a carpenter. :)


Greg

[Frankmc]

Hi Jason

Jaycar do have a 24vdc fan, check out their website.....If you wanted to connect a 12v fan to the 24v supply best connect it via a 12v dc regulator..eg 7812 ...(which is good for 1 amp).....Personally i would try and source a 24v dc one,,,,

HTH
Frank

[Greolt]

Yeah you could use a 12v regulator but better put a heatsink on I think. Clip on one should do.

Jaycar's 24v fan is $30. A 5w resistor is 30c. That's what I would do. I think I must have Scottish blood in me. :)

Greg

[rodm]

Hi Jason,
You have to pick up 5 volt Dc from the Xylotex board - VCC
Have a look here and it describes it better than I can
http://www.solsylva.com/cnc/xylotex.shtml
They are running limit switches on this setup but the touchplate is exactly the same except you run the earth to your machine or to an alligator clip. I ended up with a 100 ohm 1/4 watt resistor before mine would work.
As Greg says any input pin in the parallel port will work.

[jb2060]

Hi Jason,
You have to pick up 5 volt Dc from the Xylotex board - VCC
Have a look here and it describes it better than I can
http://www.solsylva.com/cnc/xylotex.shtml
They are running limit switches on this setup but the touchplate is exactly the same except you run the earth to your machine or to an alligator clip. I ended up with a 100 ohm 1/4 watt resistor before mine would work.
As Greg says any input pin in the parallel port will work.

thanks Rod, I did consider the VCC might have been an option because of the 5V output (maybe some of this stuff is sinking in!).

Well, I ended up connecting the touch plate wire (with resistor attached) to P15 and the earth wire to the ground PIN. Configured the Probe setting in Mach3 to PIN15 and it worked.

Greg, I reversed the Y limit setting and that worked also. Previously I had just changed the Y DIR low active (in ports and pins) to achieve reverse, which also seemed to work. many thanks...

Thanks Frank, The guy on the phone at Jaycar said they don't stock them (should have checked the web, I know) . I will front up tomorrow and buy a 24V fan. I would be more comfortable just plugging it straight in rather than make any more mods.

Hopefully I can close off this thread soon with a picture of a very cleanly cut 3D Guitar neck...thanks