Topics

My machine was misbehaving again,
traced the issue to the PC power supply    ( it was ancient )

The symptoms if anyone gets the same, were  occasionally failed boot up  and occasional failure to run apps...  Once it was placing, it seemed to rum OK.

It seemed more like a corrupt disc, but despite various attempts to fix it, the problem persisted until I swapped out the PSU

These old machines take a bit of nursing sometimes.. !

I'm trying to set up a very simple feeder

It is strips of a reel of LEDs too wide to fit any of my feeders ( about 1 inch wide)

the component pitch is 12mm and the strip I can mount is about 20 units long..

I can't seem to find the documentation on how to set these up..
I've had a play but don't seem to be making progress... 

Any tips ?

Chris

ps, after the rewire and a new PC power supply, the opd lady is performing faultlessly. !
its just me thats need a hand !

Does anyone know where the permanent feeder #indexes are stored ?

I get a bit frustrated that I manually edit them, they work OK but they are not stored for the next run,


A second issue is that my windows 98 seems to crash to the extent it turns off the machine if I try to use file manager..   anyone know a fix short of re-installing ?

Chris

I've always had issues with various tapes feeding,  sometime adding a fishing weight to the carrier part, sometimes abandoning the cover tape take up spool and draping the cover tape over the top and adding a weight.

One thing I tried recently which seems to help a bit is covering the parts of the parts tape path after the parts are removed ( eg the inside of the front cover of the feeder, the bottom corner of the feeder and the edge of the table)

Just plain old Teflon / PTFE self adhesive tape  ( ebay item  333966417304 )  it has a low coefficient of friction and it may be my imagination but it does seem to work.

Chris

Simply bearings have the small "O" rings for the number something head ( the one I use for 14 pin DIL chips) on a lower price at the moment

BS607 1mm Section 2.54mm Bore NITRILE Rubber O-Rings

https://simplybearings.co.uk/shop/product_info.php?products_id=82331

Been a while since I posted ( been busy with work life and scuba diving ! )

but today besides the Royal Mail outage and Paypal playing up, the RV decides to drop parts all over the place.
Couldn't figure it out, but the vacuum pump didnt sound quite right..

Then, the vacuum pipe came adrift from the head and i realised the problem,
the vacuum pipe had cracked through where it enters the head block and had been leaking,

I wouldn't have found it, but was luck I suppose that it let go altogether and started flopping round.
lost a few boards, but she's working again now..

https://www.ebay.co.uk/itm/163820904533

I use a variety of board types, currently aluminium with a white dielectric layer,

The FID cam has a real problem seeing the fiducials for auto correction.
The bare copper ( yes I know ) pads seems to reflect the red FID cam illumination almost the same as the dielectric ( copper is red)
Has anyone had the same problem and solved it ?

I'm thinking of changing the FID cam illuminator to RGB LEDs so I can adjust the colour to get the greatest contrast.
I know the illuminator will come out without disturbing the camera positon, and even if that wasn't the case, the leds could be mounted on a ring outside the camera case.

Before I waste any time on this I thought I'd ask

Do the much brighter white illuminators I know some folks have built have better contrast in theis situation ?

Is the camera sensitive to light other than red ?

Thoughts anyone ?

Someone has asked me if I know the possible reasons for a problem with their vacuum pump intermittently stopping and then a message coming up with "arm board not detected" when a job is loaded in rvplace. ( I think he is registering on the forum )

Oddly enough last week I had a similar issue..  at the end of a long run of placing ( lonfg for me, about 5-6000 components)
"arm board not detected" followed by "z axis switch not found", happened several times.. ( I then changed the "Z" axis switch, but haven't run it since)

What are the most likely causes of the "arm not detected" error?

I just changed the opto switch on my other machine and found a way of setting the position that seems to work ( on the RV4s at least)

( part number Omron EE-SA105    Mouser   653-EE-SA105 )

run the armtest program on the pc ( no need to have the main power on)

lift the "Z" axis until the number showing for "Analog 2" starts to change ( the mirror will flip down)

estimate the thickness packer you need between the mirror follower bearing and cam shaped lump of the Z axis it runs on to keep it in that position  ( on mine a bit of 1.6mm FR4 worked a treat, but this may vary  )

add just a little more packing and the "Z" axis should sit there with the "Analog 2" readout showing something between 10 and 255

Now you can remove the opto switch and fit the new one.. adjust it til the number reads the same as before.

Job done, time for a cup of tea !

Just being a bit lazy

does anyone have details for a source for the Z axis rack and pinion ( the metal version ) ?

Just sharing a method for soldering button LEDs onto aluminium boards  that seems to work pretty well.

I'd always found it hard to solder button LEDs to Ally board as even with low melt solder paste, some of the LEDs crap out at not much more than soldering temperatures.
( It depends on the LEDs themselves, I nneeded to use a particular wavelength only available from one supplier which seems to be particularly heat sensitive)

The problem was getting an even controlled heat so that the solder flowed, but the LEDs stay as cool as possible.

After several failed attempts and a lot of head scratching, I came up with this method which has 0% led Failures.

An MDF jig made in the shape of a box. The top cut just a little smaller than the pcb
One end of the box has an inlet to fit the hot air nozzle of the soldering station
the other end a couple of exhaust holes..

the temperature of the air needs to be set by experimentation, but  roughly double the soldering temperature.
(the top of the board is losing heat by convection as the bottom is absorbing heat by convection.)

In this case with the air set to 300C the boards solder perfectly, at 310, the LEDs start to fail!
my guess is that the board itself is at 310 - 20 / 2  C  or about 145C   (where 20 is ambient)

It takes a little while for the board to heat up, but because the excess hot air is being directed away (through the vents)
you can work on the board at its soldering temperature, correcting any soldiers etc.

pic below

I've been a bit concerned before about the lack of adjustment on the z axis rack
Well, it finally let me down a couple of days ago, jumping teeth.

The rack and pinion themselves are in pretty good condition but I think they may be replacements made to fit.
The teeth only just engaged in the rack. and finally jumped a tooth or to and caused a head crash ( twice  )
Once I realised what the problem was, I set about making the engagement adjustable.

I didn't take pictures as I was more concerned with fixing the issue, but it wasn't complicated, a description should be enough.

I could have stripped it right down and put the plate that the stepper mounts onto on the mill, but decided I didn't want to lose the camera calibration.

The main issue was getting plenty of light on it to see what I was doing !

So - I removed the cover, then three screws that hold the linear bearing slide in place , lifted out the whole moving part of the "Z" axis and temporarily fixed it to the top of the arm with an elastic band.

I then taped a protective bit of paper over the mirror.

Then out came the top stepper mounting screw ( the cylindrical spacer between the plate and stepper will drop down)
The hole for the mounting screw  is just over 3mm diameter and is counterbored.

At this point, I  used  a dremel type tool in to elongate the 3mm part of the hole toward the right, as far as the edge of the counterbore.  ( about 2mm )

The whole area was then cleaned up with a vacuum and airline

To reassemble, you need to get the spacer on the screw, so the five screws that hold the main plate to the arm came out next and the plate comes off, giving access to get the spacer on the screw plate.

The original screw is a capscrew M3 x 25

I replaced it with a capscrew M3 x 30 with a couple of 3mm washers.
The washers are standard diameter as anything bigger may foul the rack ( depending on the rack style you have)

Then its just a case of reassembling it all...

for the final adjustment, I loosed off the rack and ran it up and down with a bit of paper between the rack and pinion, and pushed the rack hard onto the pinion before doing up the screws. this seemed to give a nice clearance.

One other thing I did which is probably not necessary, but seemed to be a good idea... ( if you have access to a lathe or can source the spacers)  is shorten the spacers by 2mm to get more engagement on the rack.



Anyway, it all seems to be working now, except that I have to go out into a workshop at zero degrees C. to make a nozzle to continue !

the sooner we have a good source of nozzles guys, the better !


a couple of notes

one longer screw will be needed capscrew  M3 x 30  ( I have few spare if anyone needs one)

The rollpin to fix the pinion to the stepper shaft is 1.5mm  ( again, I have a few spare )

The capscrews seem to need a 2.5mm allen key ( hex wrench)

In case its of interest,
One of the calibration processes I came up with last year but didn't mention,
was a quick but accurate way to align the tool holder positions without straining my neck !

a 12mm steel ball in where the nozzle would sit
a thin bit of material on that ( I'm using a bit of aluminium pcb material)
then an 8mm steel ball on top of that

in the setup routines, go to set the tool position.. 
adjust the head until it is on top of the 8mm ball and slightly compressing the spring

looking from the front, adjust the head position until the plate is level
looking from the side,  adjust the head position until the plate is level

I would appreciate folks letting me know the actual driver settings they are using for the z axis motor
(the switches on the driver board)

The function selection dipswitch settings  (6 way dip switch)
and the step angle selection rotary switch positions ( 2    16 way rotary switches)

just to see if there is any correlation between settings and z axis issues

This has been covered in an old post,   "Re: RV4S Camera Problem"  but I'm posting it here under this title as it will be easier to find in a rush if the same happens to you


I've just had the same problem so to confirm...

Schottky Diode ( D3 )  gone short circuit on the main main circuit board of the power unit that has switched mode power supplies.

the giveaway is that all the low voltage stuff stops working ( cameras, fans, air pump etc. )  but the heatsink on the 2576 is still warm to the touch

It was the diode that is across the output of the LM2576 which drops the 36V down to 12V.

I assumed wrongly that the 2576 would be cooked by this, but it seems it has sufficient protection to withstand a short circuit almost indefinitely..

I replaced the IR80SQ045    (8A 45V diode)   with an MBR3060CT   (dual common cathode 30A 60V)  which is a completely different package
because its all I had that was big enough..

don't be tempted to use a standard silicon diode, it won't work !

Oh, and in an emergency, for speed, you might be able to cut the old diode and solder the new one to the leads without taking the board out

I just wasted a day but learned a lesson which everybody else probably already knew !

I was trying to effectively place 1W loose bead LEDs as the type I wanted were only available in this footprint.


After a bit of thought, I made a track for the vibratory feeder by using a K40 laser to engrave acrylic.
the main areas were removed just leaving tracks rather like railway lines...
the Beads stay aligned and just about keep the machine fed..
( I did celebrate at that point !    )

A few tries with different nozzle arrangements and I ended up with a spare Nozzle 5 drilled out
it fits completely over the lens and sites on the white body of the Led
This was effective at keeping the LED level when in movement.
I did however have to find a spare nozzle 5 holder ( the bit that is captive in the tool rack)
as it has a bigger diameter central hole than the others.

Once I got that sorted, I thought I had it cracked...   

However, the optical correction parameters were a nightmare.
First, they are too big to be imaged in one go..
second, the leads reflect light and sometimes appear light, and sometimes dark
third, a slight distortion of the legs also upsets the camera...  and so on
I spent the best part of a day playing with the various settings until I found the one that mattered..
set correction type to .........."No Correction" !

to be honest, I didn't think about it, I just clicked it in desperation.... !

The machine picked and placed at all sorts of weird angles correctly first time every time.

The point is, with a clunking great component like the LED, with mahoosive pads..
doesn't need to be placed any better than a mm or so...

so no correction.....     

[Acetal]

There may be better ways, but after destroying half a dozen nozzles recently i needed a way of restoring them
I'll post some pictures later but briefly


Acetal seems to stick to the original nozzles Ok with Loctite 410   instant adhesive

The adhesive glued a No 2 nozzle back together after the whole cylindrical part was knocked off,  and was back in use within 30 minutes.

where the damage was more extensive, I machined some 6mm bosses on some 8mm black Acetal

I drilled 6mm holes in the end of what otherwise would be scrap nozzles and glued the plugs in (with about 7 or 8 mm of 8mm Acetal projecting)

When it was et ( about 30 minutes) I chucked them up on my lathe (big Taylor chuck !) and machined them down

I didn't have a tailstock chuck that would take a 0.5mm drill, so I mounted the drill in a pin vice and put that in the tailstock chuck

A bit heath robinson, but the resulting nozzles work fine


I do have a little injection molding machine, and I'm very tempted to make a die to make them from scratch ..  but have more pressing things to get on with  ..

Thought I'd better start a new topic !

I should have a calibration jig ready some time next week, but in the meantime a question re the alignment of the fid cam.

It needs someone with a properly calibrated camera to check the angular alignment of the camera.

In other words, the angle of the cross hairs when the arm is in a particular position.

If anyone has seen the calibration process, they may know the correct way to set it, otherwise a protractor at the home position might be enough to get started ?

No connecttion to me, but just spotted   on eBay 

Two off  RV4s   + feeders

buy it now on eBay    £3,500

Bolton


http://www.ebay.co.uk/itm/Versatronics-RV4s-PCB-Machines-Feeders-/121978905981?