Peter's CP40 nozzle holder- Input requested

[betzt...@gmail.com]

Hello everyone. 

I am just about out of stock on Juki Nozzles and I have always had it in the back of my mind to make a CP40 holder. Now that my new machine is just about ready I feel this is a good opportunity to jump on this. I have a time crunch, I will be at the machine shop in a couple weeks so I am trying to hammer something out ASAP.

Yes you can buy a CP40 holder but the quality seems poor, with lots of runout all over the holder. Yes you can use runout compensation but I believe the basic mechanics should be better than that and you can use compensation for your worst case parts only. That is just my opinion about how this stuff should be!

Here is where I am at so far:

(Don't mind the spring sort of sitting in there, it is just for reference) So there is 3mm of travel. The "piston" will have a somewhat tight clearance (0.01mm) but the idea is that the lubricated X profile orings will serve to center the piston in the bore as well as provide vacuum sealing.

The holder currently has an OD of 16mm (same as the mounting boss of the NEMA 8 motor). I could reduce the diameter if I increase length and that will amplify runout so I think this is a good compromise. To get the diameter no larger than the motor boss I had to use pins in the slots so disassembly will not be possible. While this feels less than ideal, I don't really see why this should be an issue.

From the bottom mounting face of the stepper to the mounted nozzle tip is about 46mm. For comparison, that is about 10mm shorter than the juki nozzle holder.

My first question. Downforce.... 

- How much force (weight) should the spring take before starting to compress? 

- How much ideally at max compression? 

- How much force to slide the CP40 nozzle onto the holder?

If anyone has the robotdigg holder can you please measure these for me for comparison ?? 

Thanks all!

Peter Betz

Betz Technik Industries Ltd.

[Thorsten Wilmer]

Hi Peter

I measured (guessed)  with a kitchen scale a force of 750g to 850g - I assume there is something rubbing inside, this is why it was changing while pressing.

May be others have different values?

Kind Regards

 Thorsten

--
You received this message because you are subscribed to the Google Groups "OpenPnP" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openpnp+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/ecbe5095-d7de-4fb6-ad9d-16c3fb0ac45dn%40googlegroups.com.

[betzt...@gmail.com]

Thanks for the feedback. I assume this was for how much force you had to apply to get it to start compressing?

Peter.

[Thorsten Wilmer]

Hi Peter,

Yes, sorry missed to mention

Kind Regards

 Thorsten

betzt...@gmail.com <betzt...@gmail.com> schrieb am Fr., 12. März 2021, 17:49:

Thanks for the feedback. I assume this was for how much force you had to apply to get it to start compressing?

Peter.

--

You received this message because you are subscribed to the Google Groups "OpenPnP" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openpnp+u...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/b8518cc7-7813-4064-bcb8-6cc7d1f495f0n%40googlegroups.com.

[Harjit Singh]

Looking great.

I have an idea to use a brushless motor instead of the stepper. There are many tiny steppers that have a hollow shaft that a tube can be inserted in.

So, the idea would be to insert one of the tubes and glue it to the brushless motor's hollow shaft. 

I think since you are clamping this nozzle holder to the stepper's shaft, it might be usable.

The item I don't know as yet is the OD of the tube I'll use on the brushless motor. It probably will be around 5mm.

Would love to get your thoughts/perspective.

--
You received this message because you are subscribed to the Google Groups "OpenPnP" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openpnp+u...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/ecbe5095-d7de-4fb6-ad9d-16c3fb0ac45dn%40googlegroups.com.

[Mike Menci]

To have min runout on nozzle shaft from motor should be longer and botom part from nozzle as shorter as possible.

For nozzle changer - seals needs to have nice gap to seal cener and easy to slip off and on.... (Not to lose steps on Z stepper motor).

Mike

[betzt...@gmail.com]

Hi Harjit,

Thank you. Yes these should work with other motors as well. These will be 5mm (made on a ridiculously expensive swiss type cnc lathe), but I have a high precision set-tru collet chuck for my manual lathe so opening them up to larger diameters should be possible....

Mike,

Thanks for your input. I certainly agree with your assessment. Jason checked the effort to install the nozzle on to his Robotdigg holder and it was about 1kg. I will shoot for significantly less than that.

I am not sure if I have left a lot of room on the table to improve this however, I have tried to make this as short as possible overall. The image you used is with it extended. here is retracted. Let me know if you see any room for improvement:

In cad it is easy to loose perspective, those oring grooves are only 1mm wide. That reduced OD at the very top is only for cosmetics, perhaps it would be better to leave full diameter for maximum "rigidity". 

Peter.

[Mike Menci]

Peter

Leave the bottom nozzle part with seals as they are on original cp40 holder and modify only the upper part as per your will...

Mike

[Mike Menci]

this might help as well enclosed.

[Betz Technik Industries Ltd.]

Thanks Mike, those are all of the robotdigg one right?

[zart...@gmail.com]

I'm actually hoping to implement at least one "high-resolution" head that doesn't use a through-shaft stepper-motor - making it mechanically closer to the liteplacer (albeit more compact). I'd like to make a custom Z shaft and use gearing to couple it to a motor for more resolution/precision for large/fine-pitch parts, and also implement the spring there. Places like Misumi and McMaster Carr will machine a precision hollow shaft -- but they don't go down to 5mm OD ...6mm OD is the minimum stepdown/shaft size.  (If I could choose, I would use a 10mm just to ease part sourcing.)

Really, a nearly identical threaded adapter that has a mating surface at the bottom of the threads to flatten/align itself against the shaft ...and is actually manufactured well would go a long way to making a head-design simpler -  Failing that, I'd like an adapter that could work on a precision shaft that I could source COTS (same as your design, but with support for a larger shaft)

[Mike Menci]

I think so, yes.

[betzt...@gmail.com]

Hello All. I have prototyped the new design. Made a post on the new discourse venue. https://discourse.openpnp.org/t/peters-cp40-nozzle-holders-first-articles/21/2

Peter.

[betzt...@gmail.com]

Hi Everyone,

I just assembled the first 5 nozzle holders and the results seem very good.

Runout seems good, just like the juki nozzle holders you can rotate them on the shaft to try out different settings to find the lowest runout. Just like the juki nozzles themselves you have to actuate the piston a few times to get them to settle into their proper position. I am not sure what I will say for runout guarantee yet, but I was able to get all 5 of the first ones under 0.001" TIR with little effort.

Here is the test video: https://youtu.be/2tJNU8Mc5cI

Approximately 40g to insert the nozzle onto the holder, and about 250g to start compressing the spring. That should make auto changing pretty easy!

I added them to the site for anyone who is interested in trying them out!

https://www.betztechnik.ca/store/p53/CP40_spring_loaded_nozzle_holder_for_NEMA_8_and_NEMA_11_hollow_shaft_motors…html

Regards,

Peter.

[Jason von Nieda]

Beautiful work as always Peter! Looking forward to trying these out! Will be ordering a few today :)

Jason

--

You received this message because you are subscribed to the Google Groups "OpenPnP" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openpnp+u...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/74aeed28-54d5-4b84-9c0b-1f8fea3ea3a8n%40googlegroups.com.

[Lance Endres]

I already ordered a pair.  Looking forward to trying them out!

-Lance

[scott.t...@gmail.com]

Peter,

Is the overall height the same? Wondering if these can be swapped in without a major adjustment to the machine.

-Scott

[Mike Menci]

I agree with Peter - Better would be to have the distance from bottom of Nema8 to Nozzle tip ?

Mike

[betzt...@gmail.com]

Thanks everyone!

I appreciate the buy in, very interested to hear what you guys think of them when they arrive. 

Interesting point regarding the length compared to the juki nozzle holders. When internally justifying the thousands of dollars spent to do this machining run, I maybe falsely assumed that some people who may have already purchased juki nozzle holders, may be interested in trying these out as well. The effect of a difference in height did not cross my mind in the design phase as I was very focused on making the CP40 holder as short as possible, for runout reasons. I can see how that would be a possible issue though. 

I am going to put this information on the product page as well but the CP40 holder (with nozzle) is about 11 mm shorted than a juki nozzle holder (with nozzle). See below for visual comparison:

I am very curious to hear what you think about that difference and whether or not that is a deal-breaker for trying the CP40 nozzle holders out on your machines.

Thanks again,

Peter.

[Scott Wilson]

It'd be worse for my machine- I already had to work around x carriage clearance issues by moving your head down a bit. I'd have to move it further for this to work. Even then there are a couple things that would probably need changing like the push-pull actuator I use.

I miss the Z range of the liteplacer (but not its slow speed). More than 22mm of travel would have made a lot easier. Most of my pain putting together a new machine was designing the x carriage so that your head could reach the parts without the rest of it hitting the CL feeders.

--
You received this message because you are subscribed to a topic in the Google Groups "OpenPnP" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/openpnp/9QQQBeHBHw8/unsubscribe.
To unsubscribe from this group and all its topics, send an email to openpnp+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/7a52da95-df3e-4699-805d-fb0a927a34can%40googlegroups.com.

[Jonathan Oxer]

I ordered a couple yesterday, the moment I saw Peter's post! I couldn't get out my credit card fast enough in case they went out of stock while I was entering my details ;-)

Jon

To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/CA%2BQw0jxVPOBkawy%2BNBjiEVtec67uHLEgMb5Fb4jH6YwttxM3kQ%40mail.gmail.com.

[Ben Holmes]

I'm just in the process of getting everything together for a new pnp and want to use your heads. I was looking to purchase your full dual head kit. I really like the design of these and was wondering if they would work with your kit or if I'm going to need to do a different design.

Ben

--
You received this message because you are subscribed to a topic in the Google Groups "OpenPnP" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/openpnp/9QQQBeHBHw8/unsubscribe.
To unsubscribe from this group and all its topics, send an email to openpnp+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/7a52da95-df3e-4699-805d-fb0a927a34can%40googlegroups.com.

[betzt...@gmail.com]

Thanks for the feedback everyone. 

Scott, that is too bad to hear. My new frame design has independently adjustable (height-wise) work areas and feeder areas, for just these reasons. If you needed the feeders or main work areas to move up or down you just loosen the screws and move them up or down and tighten. 

Thanks for that Jon, I hope you like them!

Ben, yes these will work with the new heads, if a person ordered a head they could select the juki nozzle option and in the order notes you can say CP40 holders and I will supply them for the juki price until I can update the product page.

Peter.

[Sandra Carroll]

From the video you’re using a 10^th indicator.  With about 1.5 to 2 10^th runout which is great.

What is the runout of the motor shaft?  

Curious to know how much of that run out is the part or the shaft.

 

Sandra

 

From: ope...@googlegroups.com <ope...@googlegroups.com> On Behalf Of betzt...@gmail.com
Sent: Tuesday, April 27, 2021 3:19 PM
To: OpenPnP <ope...@googlegroups.com>
Subject: Re: [OpenPnP] Peter's CP40 nozzle holder- Input requested

 

Hi Everyone,

 

I just assembled the first 5 nozzle holders and the results seem very good.

 

 

Runout seems good, just like the juki nozzle holders you can rotate them on the shaft to try out different settings to find the lowest runout. Just like the juki nozzles themselves you have to actuate the piston a few times to get them to settle into their proper position. I am not sure what I will say for runout guarantee yet, but I was able to get all 5 of the first ones under 0.001" TIR with little effort.

Here is the test video: https://youtu.be/2tJNU8Mc5cI

Approximately 40g to insert the nozzle onto the holder, and about 250g to start compressing the spring. That should make auto changing pretty easy!

I added them to the site for anyone who is interested in trying them out!

https://www.betztechnik.ca/store/p53/CP40_spring_loaded_nozzle_holder_for_NEMA_8_and_NEMA_11_hollow_shaft_motors…html

Regards,

Peter.

--

You received this message because you are subscribed to the Google Groups "OpenPnP" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openpnp+u...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/74aeed28-54d5-4b84-9c0b-1f8fea3ea3a8n%40googlegroups.com.

[Betz Technik Industries Ltd.]

Hi Sandra,

 

There is typically zero runout detectable on the shaft (from my experience). I’m not sure if that is due to the magnetics of the motor or what but it seems impressive.

 

It is deceiving measuring the tip of the nozzle holder as the dial test indicator can place enough pressure on the piston to deform the O-rings. I’ve found the best way to test them is just visually. It seems that when assembly goes well, there is no visual wobble at the tip. If there is a little wobble visible, usually just a hand actuation of the piston aligns everything.

 

Regards,

Peter.

 

Sent from Mail for Windows 10

[Jonathan Oxer]

A pair of Peter's CP40 holders arrived today, and I can confirm that they're just as beautifully crafted as I hoped they'd be :-)

The fit with CP40 nozzles is perfect. They slide in smoothly and easily but the tip stays exactly where it should. Doing nozzle changes with these should be really easy.

Because of the decreased tip distance compared to the Juki holders already on my machine, I'm making new stepper mounts to move the motors down and bring the tips to the same height as they were with the Juki nozzles. Hopefully I'll be running jobs with the CP40 nozzles in the next day or two. So far the conversion has been quite painless.

Thanks Peter!

Cheers

Jon

--

You received this message because you are subscribed to the Google Groups "OpenPnP" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openpnp+u...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/64D2058F-89E4-4FEF-A308-35930595E7F5%40hxcore.ol.

[betzt...@gmail.com]

Hello Jon,

Thank you for the feedback! The more I play with them the more I like them. 

Regards,

Peter.

[Harjit Singh]

Peter, what are your thoughts on being able to add some feature(s) to your CP40 nozzle holder such that we can use it to probe/detect when it has touched something?

To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/f3ed71f0-3bcb-4283-a54e-5f9e1f3e4561n%40googlegroups.com.

[Lance Endres]

Hi Peter,

I have been experimenting with your nozzle adapters and comparing them to the CP40 Samsung Nozzle Adapter and the Juki nozzle tips.  There seems to be an issue when a vacuum is pulled on yours.  The adapter can get stuck in the retracted position (see the video link for a demonstration of all three).

https://youtu.be/_r6hrhfN1sE

It seems to be a combination of a few things are colluding to create the problem.  

- From the looks of the cross-section, there are some interior surfaces that are allowing the vacuum to counter the spring force (see image).  

- There is a larger cavity on the interior than say the Juki nozzle tip.  That's going to make it harder to extend the bottom while under vacuum.

- The Juki nozzle tips and CP40 have almost zero friction while extending and retracting.  Yours doesn't have much, but that little extra friction contributes to the issue.

- It seems like the Juki nozzle tips and CP40 have stiffer springs.

[betzt...@gmail.com]

Hello all!!

Thank you for the feedback. I have used them on 3 production runs here in the shop and overall I am very happy with them.

A couple people (like Lance above) have reported that their nozzle holders A) retract with vacuum on, or B) get stuck when you fully compress them to the stop if vacuum is on.

A)- Although most people (myself included) have not experienced this, I concede that I went too light on the spring pressure. I did some experimenting in the shop and shimmed the springs. The effect was very consistent, 20g increase per shim. I settled on two shims for unit for a total increase of 40g. On the next run we will have them machined differently to compress the springs by the same amount, but for now we will shim all new units that go out the door. If anyone wants to exchange their units I would be happy to do that, you can email me to set it up.

B) This issue is actually caused by "wringing" of the two parts. They are machined flat enough that when you press them together they stick, almost like they are magnetic. The little bit of oil and grease found in that area also adds to the effect. The increased spring pressure from the fix above overcomes this force, but on the next run we will machine these to be not perfectly parallel. 

Thanks everyone!

Regards,

Peter.

[Lance Endres]

Great news, Peter!

-Lance