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Topics - Mike

#2
So after a 2AM repair session to get the machine working for a job that _HAS_ to be done over this weekend....

I discovered what an utterly  terrible idea it was to mix mains and RS232 on the feeder connectors.
Job was all set up for PCBs arriving next day, decided to move a feeder, and suddenly, all feeders not working.
I figured it would be a serial port issue, ran feedertest on a laptop to verify the feeders were OK, then troubleshooting the dead PC serial port.

Mine is the type that has the two COM ports on the DSP board, and instead of proper UARTs, they use 87C51 microcontrollers for some bizarre reason. For a 9600 baud tx-only interface FFS - what planet were they on?
It took out not only the RS232 driver but this MCU. Luckily I had a pile of scrap boards ( Thanks Cubik!), and I got one to work with armtest, verifying that it had a good MCU for COM1.
All the DSP boards I had which didn't hang the PC seemed to have the same fault, so clearly a definite issue.

One thing I found - the feedertest utility doesn't seem to work through the DSP board UARTS - I initially tried to bypass the DSP board and run via the PC COM ports - I had feedertest running via the PC COM port but not in RVPlace. I'm not sure if the ports on the DSP even act like normal COM ports.

I assume there is some way to get the RV to not use the DSP card ports and use the PC ones - anyone know details ?
I was getting too desperate and sleep-deprived to wait through yet more WIN98 reboots to experiment.

I can't understand why they did the feeders like this - only one ever needs power at a time so a 24V supply from the main box would have been a much better solution - cheaper, safer and would allow cheaper connectors. Not to mention using RS232 and +/- supplies for the receivers when RS422 would have actually used fewer wires and no need for oddball bipolar supplies.
I guess there is probably some history there but it boggles the mind how they came up with such an obviously terrible design given that the rest of the machine is pretty reasonable.

I've now put a local mains power switch in line with the feeder cable, and a tranzorb on the serial line.

Rant over...










#3
Simple spacer to allow 16mm lanes to be used with 12mm tape
#4
RV Hardware / 3D printed tape holders
June 18, 2023, 02:36:35 PM
Passive tape holders.
30 x 4mm long ( limit of passive feeder length in RV software)
Tape retained by friction-fit bar ( left of image)
Has bumps at side and edns to help stacking.
Takes 5 dia x 3 high neodymium magnet-  press fit but suggest putting a drop of cyanoacrylate glue from the top to secure- make sure magnet is completely flush.
As-is, the fixing to the base plate is a bit slippery, so I added cavities on the underside to take some soft feet
https://www.rapidonline.com/r-tech-310000-pu-round-protective-feet-6-4-x-1-9-clear-sheet-255-31-0000
You could maybe make something similar in TPU. 

The wide ones could probably do with being longer & deeper for taller parts - I'll probably do these as & when needed, as Tinkercad was getting annoyingly slow with all variants in one design
Tinkercad link https://www.tinkercad.com/things/6ix3NnzxHmA

Zip of STLs below

tapeholders.zip
#5
RV Hardware / 3D printed PCB corner block
June 18, 2023, 02:23:36 PM
3D printed PCB corner block.
Print the base and two of the screw STLs.
Screws are held in place with M3x16 screw, washer and spring ( approx 8 dia x 10mm long)
Takes two 10mm dia x 5mm high Neodumium magnets
#6
Having just got a 3D printer, I thought I'd have a go at improving the problem I'm always having of the belts on the cover-tape spools slipping, leading to inadequate peel.

I've done a design which adds knobbly bits to the belt part of the reel, and this definitely has better grip ( tested by passing a belt over this and a normal reel and seeing which slips first).

Not tested in anger yet - printing a couple of feeders' worth of them now. Could be that it's too grippy, but sharing files here in case anyone else wants to give it a go.

Tinkercad link to model : https://www.tinkercad.com/things/lPaYhVs57R6
STL files attached
#8
RV Hardware / Another feeder improvement mod
November 12, 2022, 12:54:05 PM
So once again getting frustrated about how often the cover tape wasn't quite pulling hard enough, I had a close look at what was happenning - I'd always assumed the main issue was the belt slipping on the tape.
However I noticed that in some cases it was actually the belt slipping on the take-up reel pulley.
I've roughed up the pulley inner surface, using a needle file mounted in my pillar drill, and this seems to have made a noticeable improvement.
(I use the orange belts from polymax, which seem to be better than the black ones)


#9
https://www.aliexpress.com/item/1005004587777050.html?spm=a2g0o.productlist.0.0.721c6d8bw165km&algo_pvid=4462904b-f71f-4f43-9c85-19923949e18c&algo_exp_id=4462904b-f71f-4f43-9c85-19923949e18c-8&pdp_ext_f=%7B%22sku_id%22%3A%2212000029733487900%22%7D&pdp_npi=2%40dis%21GBP%212436.03%212436.03%21%21%21%21%21%402100bde316594280863917280e53c3%2112000029733487900%21sea

https://www.youtube.com/watch?v=kpelBwOVKMY

Looks interesting - some nice features for low-volume users:
Bulk feeder - would be interesting to see how well this works in practice
Decent 315x350+mm board area ( if only one feeder bank in use)
Tool changing, which is an essential feature lacking in many low-end machines, 3 + 1 nozzles is just about enough.


The only thing I'd have liked to have seen is a flying camera option for part vision, as this would improve speed considerably for relatively low cost
Also the option to take a few Yamaha feeders for high-quantity parts would be nice

Some things I'd like to see in more detail:
Feeder loading procedure
How do the feeders pull the cover tape
Feeder options for wider/deeper tapes

Is the speed shown in the videos the maximum speed ? It does look a little slow - the 3000cph claim looks suspect
#11
General SMT / AI powered cloud AOI service
November 23, 2020, 10:33:18 PM
Thought this might be of interest to anyone contemplating AOI :

https://www.eevblog.com/forum/eda/neural-network-powered-assembled-pcb-inspection-tool-(aoi)/
#12
Part of a lot I picked up a while ago - RV1S base unit only with PSU box and PC. No frame,feeders,nozzles or PCB holders. I did have it running a while ago but it's just been sitting gathering dust since.
I have an RV4s so not likely to be very useful for parts & now want to clear the space, and I can't be arsed to set it up again to demo to a potential buyer, so prefer to go to someone already familiar with the machines as a spare. 
Collection only Loughton Essex
#14
RV Software / The annoying screen-shift issue in RVPlace
November 27, 2018, 06:44:57 PM
One of the few actively buggy things in RVPlace is that the screen layout in the first screen will randomly get an offset when exiting from the Place screen.

This is only an issue for selecting/omitting parts, but can be really annoying if it happens during job setup. If you don't need to do component selection etc. you can get back to the place screen, and most other functions by waving the mouse around the menu area and you'll see the menu text appear through the corrupted image.

The fastest workaround is to load any other job file ( ignore errors about feeder mismatch), then reload the previous job.

Exiting and re-entering RVPlace also fixes it but you then have to wait while it re-homes the arm.

I'm assuming this is a common issue and not something peculiar to my machines - can anyone else confirm - would be interesting to know if anyone has never seen this, as this may point to a PC issue ( or a Place.DLL issue). 

#15
RV Software / Notes on different versions of PLACE.DLL
November 27, 2018, 06:32:12 PM
There is an issue with place.dll. Basically, there are 2 versions..
The following extract courtesy Alex Wilkinson:

There are two versions of Place.dll that I am aware of: an older one dated 22/12/1999 size 1774k, and a newer one dated 12/9/2001 size 268k. Both have different issues, however the older, larger version seems to be more usable in most instances.

Place.dll, 268k version.
If you set the machine to 'auto fid correct' then the first component picked after the fid correction will fail because the head lingers longer than usual in the lowered pick position, and before it retracts with the part it commands the feeder to index, so the head retracts after the tape has started to move, therefore it loses the part.

Place.dll, 1774k version.
The issue above in the 268k version is resolved, however instead there are a whole load of other problems related to larger parts and multi-indexing.
If a part is too large to vision in a single shot, therefore requiring 2 or 4 images to be taken of it, then the feeder where it came from is sent one index command less than its set to (the first one is missing, not the last) regardless of the number of indexes setting in the software. You can only set a maximum of 3 indexes per part I think (larger numbers are accepted but treated as if 3). This means large parts that require more than 2 indexes (3-1) can't be placed without multiple mispick errors each time. If the part came from a tray, then the machine always goes back to the same pocket to pick the part, even though its just taken the part from there. Picking from a vib feeder works ok as no indexes are involved.
Setting 'force fixed' in the CDF settings for a package will mean the machine only takes a single image of the part, even if its too big to vision properly. This does mean the indexes work correctly again for that package, but in reality is only really useful for parts that are only slightly too big for a single image vision normally.

Also if a part requiring 2 or 4 images fails vision analysis, the machine will go back and retry endlessly, ignoring the 'number of retries' setting, and without feeding at all as the first index command is missing and a vision failure only produces one index command.
My solution to this in most cases is to use a new design feeder controller board in the larger lane feeders, and then you can set (faster) multi indexes using the 4 spare dip switches on the feeder and the PC is then set to only send one index command for that part.

Conclusion

268k DLL version used for most jobs as this avoids all the problems with larger parts on tape or in trays. You just have to manually do the fiducials each run or accept the first part picked will be lost. For boards with just small parts where auto fid correct is useful then the 1774k DLL can be used.
#17
RV Software / "Shift required too big"
May 08, 2018, 12:10:27 PM
Has anyone found a workaround for situations where RV place complains that corrections are too big so it refuses to place - having problems with large parts from passive feeders where pic location is a little inprecise.
I'd rather not use "no correction" as it won't detect mis-picks
I can't any obvious limit values anywhere