placing elctrolytics

Post Reply
danmcb
Posts: 27
Joined: Wed May 13, 2015 5:22 pm

placing elctrolytics

Post by danmcb »

this looks really interesting. Just want to check : can the machine place electrolytics, like this?

http://be.farnell.com/multicomp/mcesl25 ... st=1870611

If so, what is the size limit? some of them run quite bic.

Also, what about stuff like SM relays and so on?

thanks!
JuKu
Site Admin
Posts: 1114
Joined: Thu Feb 14, 2013 3:06 pm
Location: Tampere, Finland
Contact:

Re: placing elctrolytics

Post by JuKu »

This size limit question starts to be a FAQ. :-) when I get back to my office, I need to run some tests to find the actual limits. In the meanwhile:

You need to change the needle between small and large parts. A needle small enough for small passives does not have enough grip for bigger parts. The software supports this, and you can arrange the placement order so, that all small parts are done first, then insert a needle change, then do big parts. The kit comes with a set of different size needles ans rubber cups for bigger parties.

The machine can handle commonly used parts, such as electrolytics and ICs. Of course there are limits: some parts are not that well suited for vacuum pickup, and a bulkier and hevier a part is, the lower its center of mass is compared to grip point, so acceleration can twist them off. (You can tune the acceleration, btw.) And ultimately, some parts are just too heavy. I don't think it can lift a touchscreen, for example. But as said, I don't have a better idea than "normal parts are ok".
danmcb
Posts: 27
Joined: Wed May 13, 2015 5:22 pm

Re: placing elctrolytics

Post by danmcb »

ok, that's good enough for now ;-)
mrandt
Posts: 407
Joined: Mon Apr 27, 2015 10:56 am
Location: Stuttgart, Germany

Re: placing elctrolytics

Post by mrandt »

Hi Dan, hi Juha,

I just tried to pick and place a 5mm x 5.3mm electrolytic cap - worked without issues at full speed.

I used a 21G needle (0.8mm x 22mm, usually green) which has an outer diameter of about ~1.2 mm. It holds the part with or without a rubber cup:
lifting 5x5.3mm electrolytic cap - with rubber cup attached to needle
lifting 5x5.3mm electrolytic cap - with rubber cup attached to needle
electrolytic_1.jpg (35.27 KiB) Viewed 3675 times
lifting 5x5.3mm electrolytic cap - with just the needle
lifting 5x5.3mm electrolytic cap - with just the needle
electrolytic_2.jpg (27.51 KiB) Viewed 3675 times
Please note that I am not using the original vacuum pump from the kit but my own, modified pneumatic system which generates a negative pressure of about -0.6 bar. I am not sure how strong suction of the kit pump is, so results may vary. But as you see, it is definetly possible with this machine.

Regarding other components: I can place many sorts of 0805 and 0603 passives, ceramic caps in plastic case, inductors and micro USB and Wago terminal blocks. ICs I have not tried larger than TQFP44 and SOIC-8.

Generally speaking I assume that, as long as your pump generates enough suction and you use a large enough needle, you can lift quite large components. A rubber adapter matching your part helps. On a side note, it is fairly easy to make such adapter from silicone yourself if you have to place really odd components.

As Juha pointed out, you need to slow down movement to not loose the part due to acceleration of machine / inertia of the part or even air friction. Maybe this should be a feature request? Configure maximum acceleration and maybe speed per component? Could be done in tape setup :idea:

Cheers
Malte
Post Reply