Better nozzle with auto change?

[gtrplaya101]

Since I posted this on the OpenPnP forum as well, I mention it here as well: I'm planning to offer a set of nozzles, the adapter and a re-designed holder in the shop later, together with an upgrade kit for the machine. An official announcement will come once I have pictures of the prototypes and pricing.

Any clue how long this might be? Hadn't checked in on the forum in a while and really happy with the direction things are headed! The nozzle changer would be a huge bonus for me. Would we be talking weeks or months?

[JuKu]

A few weeks, I suppose. Please subscribe to the mailing list if you already haven't done so; that way, you'll get the notice.

[KevinA]

After buying and trying some 'needle flat tip' with .25" NPT threaded holder I wanted a means to 'auto-change' the tool. I first looked at the Juki but found no 'nozzle holder' other then one that required adjusting run-out every time you changed the nozzle. I looked at the Samsung CP40 and CP45NEO or CP45FV, I found the NEMA11 motors with threaded shafts but was wondering if anyone has measured the run-out of each type of the Samsung holders?
Thanks

[vonnieda]

After buying and trying some 'needle flat tip' with .25" NPT threaded holder I wanted a means to 'auto-change' the tool. I first looked at the Juki but found no 'nozzle holder' other then one that required adjusting run-out every time you changed the nozzle. I looked at the Samsung CP40 and CP45NEO or CP45FV, I found the NEMA11 motors with threaded shafts but was wondering if anyone has measured the run-out of each type of the Samsung holders?
Thanks

It's pretty bad. Have a look at the videos in my YouTube channel where I tested runout on a bunch of motors, adapters and nozzles: https://www.youtube.com/channel/UCUmr1p ... kgg/videos

You recognize the videos by the yellow vice shown in each thumbnail.

Jason

[mrandt]

After buying and trying some 'needle flat tip' with .25" NPT threaded holder I wanted a means to 'auto-change' the tool. I first looked at the Juki but found no 'nozzle holder' other then one that required adjusting run-out every time you changed the nozzle. I looked at the Samsung CP40 and CP45NEO or CP45FV, I found the NEMA11 motors with threaded shafts but was wondering if anyone has measured the run-out of each type of the Samsung holders?
Thanks

Hello Kevin,

I also tried a bunch of different nozzles:

- Blunt needles worked better when I exchanged the luer lock holding them for one made from metal; I also 3D-printed some reinforcements for the needle which would reduce bend and runout; but that does not help for auto change. The luer lock I have has a M5 outer thread on the other end which nicely mates with my modified A-axis (see here: http://liteplacer.com/phpBB/viewtopic.p ... =251#p1736).

- I then ordered the famous Juki 5xx nozzles and tried several holders made in China; while the nozzles were fine, the holders were all were impresicely manufactured, had runout or problems with the ball-lock release; making auto change impossible.

- I then ventured in the land of Korean solutions and got some CP40 nozzles. I found a holder which also had M5 thread, so it was quickly attached to the A-tube; runout was not much of an issue.
The nozzles were also really nice but the holder (again made in China) had severe vacuum leakage; to the point were it became impossible to use without replacing the vacuum system.

- Finally Ray offered his precision-made Juki holders over on OpenPNP Google Group and I bought two of those. What shall I say? They work flawlessly and have very little runout; mostly depending on the quality of the Juki nozzle attached to it.

The latter are designed to be press-fitted onto a NEMA8 hollow shaft stepper (available from RobotDigg). While such motor can be attached to LitePlacer Z-axis using a different plate, it will effectively lower the rotational resolution compared to the existing solution - to 1.8° while on the original it is 0.9° plus some gearing, so even less.

The other drawback is that you will lose the Z-height probing, which Juha ingeniously built into the A-tube with the spring and extra switch.

But hey, nothing's perfect. I will try to evaluate several ways of attaching Ray's Juki holders to my machine and will report back which worked best

[KevinA]

After buying and trying some 'needle flat tip' with .25" NPT threaded holder I wanted a means to 'auto-change' the tool. I first looked at the Juki but found no 'nozzle holder' other then one that required adjusting run-out every time you changed the nozzle. I looked at the Samsung CP40 and CP45NEO or CP45FV, I found the NEMA11 motors with threaded shafts but was wondering if anyone has measured the run-out of each type of the Samsung holders?
Thanks

It's pretty bad. Have a look at the videos in my YouTube channel where I tested runout on a bunch of motors, adapters and nozzles: https://www.youtube.com/channel/UCUmr1p ... kgg/videos

You recognize the videos by the yellow vice shown in each thumbnail.

Jason

ECK! https://www.youtube.com/watch?v=_U12TWbuFhg Any chance of checking the holder only? I suspect that that setup was with the 5mm shafted motor you measured with zero runout? Viewed Youtube and scrolled down to your explanation:4mm
Thanks

[KevinA]

snip / to 1.8° while on the original it is 0.9° plus some gearing, so even less.

If I have a 1.8° step and my driver is set to 1/32 doesn't that mean I'm way beyond the resolution needed? Torque is not an issue nor in speed.

[vonnieda]

After buying and trying some 'needle flat tip' with .25" NPT threaded holder I wanted a means to 'auto-change' the tool. I first looked at the Juki but found no 'nozzle holder' other then one that required adjusting run-out every time you changed the nozzle. I looked at the Samsung CP40 and CP45NEO or CP45FV, I found the NEMA11 motors with threaded shafts but was wondering if anyone has measured the run-out of each type of the Samsung holders?
Thanks

It's pretty bad. Have a look at the videos in my YouTube channel where I tested runout on a bunch of motors, adapters and nozzles: https://www.youtube.com/channel/UCUmr1p ... kgg/videos

You recognize the videos by the yellow vice shown in each thumbnail.

Jason

ECK! https://www.youtube.com/watch?v=_U12TWbuFhg Any chance of checking the holder only? I suspect that that setup was with the 5mm shafted motor you measured with zero runout? Viewed Youtube and scrolled down to your explanation:4mm
Thanks

Sorry, all my gear is packed away and won't be unpacked for a month. I'm in the middle of a cross country move.

[mrandt]

If I have a 1.8° step and my driver is set to 1/32 doesn't that mean I'm way beyond the resolution needed? Torque is not an issue nor in speed.[/quote]

I doubt that microstepping will help much; especially witht the small motors. Would be interesting to conduct some experiments with regards to repeatability; I guess you'd be surprised how random the results would seem.

The necessary precision is another interesting question. It mostly depends on the size of the parts you want to place and their pitch - as farther away the leads are from the center, the more XY offset you get for a given rotation.

For smaller parts and passives 1.8° is OK, for large QFP or similar it might not be good enough.

There has been extensive discussion about rotational precision needed and micro-step-ability at OpenPNP group - just search their forum for it.

[KevinA]

Sorry, all my gear is packed away and won't be unpacked for a month. I'm in the middle of a cross country move.

Have fun during the move (the unloading is a pain), I've still got boxes I haven't opened from moves 20 years ago, working on it....