Faster paste head motor speed

[Chris]

One thing I have noticed repeatedly when using solder paste, is the cog takes “some time” to turn and there is a small delay before paste actually starts flowing. sub 300 feedrate is about as fast as I can get it to go.

The problem being faster than 300, it actually misses the start of very small pads because the cog has not finished turning all the way yet and by the time it has, it has already passed over half of the pad.

A simple solution would be to allow the head cog speed to be set, like twice as fast. I am sure the printer is capable of reaching higher speeds than 300.

A possible workaround could be to add a delay before actually moving over the pads. Which would give the chance to the cog to fully turn before it actually starts moving over pad.

[mewertow]

Hi @Chris,

If you’re missing the starts or ends of your pads, you’ll want to adjust your Soft Start Ratio and Soft Stop Ratio in the settings window (description on this page). These are ratios that go from 0 to 1. As the V-One applies the kick, the flow rate will increase from 0 to max flow rate, and these settings allow you to control at which point in that transition your trace will start. A definition is ‘the proportion of the kick that is performed while travelling in the z-axis’ - meaning, if you have a soft start ratio of 1, then you will have completed the kick when you begin the trace, while a soft start of 0 would start applying the kick when you begin your trace. The inverse is true for soft stop (which controls the end of the trace).

I hope that helps!

-Matt

[Chris]

Hello @mewertow Thanks for your input.

I have these settings currently.

But soft start ratio only seems to effect the line after the kick has happened. With a lower value it seems to do the kick apply paste, then “fades out” as it draws the paste. Setting to 1.00 seems to help.

But on that basis, it doesn’t help anyway with my problem, as the paste cog is still turning while its moving axis (drawing the paste on the pad). It actually says in the software “The portion of the kick applied after the start of a dispensed line”. Point being after , as it it does the kick first, then after it does the soft start ratio. But again it’s to late anyway.

So the order is ?

kick - soft start ratio - Soft stop ratio

where kick is the start of it dispensing paste on the pad… but the kick doesn’t happen fast enough. As by the time it has done the kick, its already passed over half the pad. The only solution is as I mentioned, to use a slower speed. 150 is what I am currently at. But i’ve had to run right down to 20 in some cases.

The softstop is 0.25 because I think the paste is still flowing when it stops drawing , it actually ends the pad fine otherwise.

Its why I think something is a bit off with the order things happen. It should (or have the option) to complete the kick fully before moving the axis drawing the paste on the pad. Currently this doesn’t happen. I can only slow the speed down to make sure the kick has more time to complete before actually moving over the pads drawing the paste.

I will look at it again tomorrow. Though I don’t think it completes the kick in the Z-axis movements. Starts it yes, but the XY axis is moving while its still doing the kick. Which is the problem I have.

[Chris]

Actually if you look at this video at 0.25 speed…

Even though the tip is moving to the right very slow, you can hear the cog is still applying the kick while its actually moving to the right.

Feedrate speed would be 20-30 in the video. As you could imagine, if it was running 300+ it would still be doing the kick half way across the pad. Which is why I have to slow it right down to get the full pad drawn.

[mewertow]

Hey @Chris, sorry about that - you’re right, my definition is incorrect, the soft start/stop are the proportion of the kick that is done in XY. Meaning a soft start of 1 will begin to apply pressure only after the nozzle has descended in Z and begins to move in XY, while close to 0 will do the opposite.

Maybe the images below will help clarify. In both, the black arrows show the path the dispenser tip follows - first it descends in Z, then travels in X, then raises in Z. The Blue block shows at what point in the start the kick is applied, while the Red block shows at what point at the end it retracts.

As you can see, when the soft start / stop ratio are set to 1, the kick is applied and retracted entirely during the X travel:

When they are set to 0.5, it is done half during the Z travel, half during the X travel:

It turns out there’s a bug that prevents lowering all the way down to 0 for the soft start and soft stop ratios, which is why they’re capped at 0.05, which may be the reason why your very small pads get missed - I’ll make a note. One approach would be to try reducing your kick value, as long as you can still calibrate decently well with the fine tuning (+/-) before your print.

If you’re still running into trouble, I’d highly suggest following up with @MikeL over the support chat in the app - I just happened to be looking over the forum today but usually it’s not monitored closely - if you message in the app, you’ll be able to get help much faster.

-Matt

[Chris]

@mewertow Thank you very much for your explanation.I did not realise part of the kick was relating to the soft start ratio.

I have just tried setting it back to 0.05 ( as you say it will not do zero which would actually be better) I’m only printing a low speed at the moment but I can see the pads look fine with how the paste is being applied. It looks like 90% kick happens in the Z-axis which is a lot better than before. I will move to a higher speed and test things out more later on.

I do still think having a faster motor speed if possible would still be an advantage. As when using finer tipped nozzles and a lot more kick value is needed, and it does take two or three seconds to complete the kick.

It could also be an advantage to have the option in the software to “exaggerate” the tool paths. I’m currently using a large diameter nozzle so I only have to pass over the pads once. I can of course alter the pass spacing which is a great feature. But if it was possible to elongate the paste on the pads it would help with fine tuning the exact amount of paste.

It may sound like a silly option, but sometimes the paste gerber data is actually physically smaller than the actual copper pad. While this is really a PCB problem, it does take a lot of time when you are dealing with hundreds of parts with hundreds of pins on. So if there was a new feature to exaggerate the paste data, that as well would be a really useful feature. Just some sort of " increase pad size by X percentage" option.

I was not having troubles exactly, my post was a feature request rather than a technical support request. I have chatted to Mike several times in the chat and he has always been extremely helpful.