Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Dedicated or adjustable fixtures for Universal Radial Inserter

Views: 6036

#51577

Dedicated or adjustable fixtures for Universal Radial Inserter | 28 August, 2007

I'm using a separate thread related to another thread because I didn't think it appropriate to 'pile on' to my tale of woe. This question is strickly operational: - . - . - . - . - . - . - . - . - . - . - . - . - . - In using a Universal Radial Inserter, we have been told two separate pieces of advice:

(1) use a adjustable fixture that is capable of handling many types of boards. (2) use a dedicated fixture that only fits one type of board

(1) is a cost advantage, but I think the risks are that there will be false starts due to board installation issues (2) costs more money for fixtures costing about $500 per board type, but manufacturing can make a switch from one type to another more easily

Does anyone have any advice from experience on this? Am I missing something?

reply »

#51578

Dedicated or adjustable fixtures for Universal Radial Inserter | 28 August, 2007

Dedicated fixtures are always better, assuming you use a good manufacturer. If your a CM you will always have a battle convincing customers to pay for dedicated fixtures unless you have a detailed cost structure that can show them how they will save money every time you change over by reducing their set up time. Then of course you have to reduce their price. If you are going to save time in reduced set up and they are willing to pay your quoted price (with the universal tooling set up buried in it) then it would be wise for your company to buy the dedicated fixtures, recoup your cost over a couple of runs and then once they are covered�.. less hassle, more profit for you every time you run the job!

reply »

#51591

Dedicated or adjustable fixtures for Universal Radial Inserter | 28 August, 2007

dedicated fixture works best if the board is very much populated. But if the parts to be inserted are less than 300components, adjustable fixtures may be used. But the secret of good insertion is a precisely measured tooling pin to prevent the boards from moving caused by machine vibration. even 2thou movement will be prone to insert errors.

reply »

#51592

Dedicated or adjustable fixtures for Universal Radial Inserter | 29 August, 2007

The two factories I've worked at that ran Radial Lead inserter/sequencers were both building their own products and we were able to specify our own panelization guidelines. One-half inch rectangular frame on all boards.

Our universal workboard holders were made by Fancourt and worked fine if the tooling pins were between .121-124" dia. for our 125" holes. Anything smaller and we had insertion issues, especially where we were pushing the lead diameter max. spec.

The tough part was keeping good pins in stock. We eventually got ahold of a bunch of titanium nitride coated pins and that cut pin replacement way down.

If you're running irregularly shaped boards w/o panels custom pallets is probably the way to go. You can still have them made to mount on your universal workboard holder.

reply »

#51602

Dedicated or adjustable fixtures for Universal Radial Inserter | 29 August, 2007

Thank you for the answers to my questions.

We are running two-lead LED insertions. Most of our PCBs are square between 9" and 14.25" in a 16 x 16 array, so pitch ranges from 0.52" to 0.90". Further complications are that most of the boards have three LED colors per location, so that we have 16 x 16 x 3 = 768 LED placement PCB job.

Management is trying to avoid the expense of buying new fixtures, but the adjustable one that we have is fairly old and 'sloppy.' We have two that work and we are trying. The company that lent them to us has offered to sell them for $300 each which I feel is fair, but so far I don't have authorization to purchase these.

reply »

#51603

Dedicated or adjustable fixtures for Universal Radial Inserter | 29 August, 2007

A ssume that were talking two-lead LEDS with 2.5mm pitch or lead-to-lead distance. Just a question: are the LED terminals shape were Square or the naturally rounded? Due to different insert rotations, you may wish to do program off-sets per rotation specially if your insertion head is not dialled properly.

reply »

#51607

Dedicated or adjustable fixtures for Universal Radial Inserter | 30 August, 2007

The dedicated fixture never really wears-out. You may need to change tooling pins and hold-down tabs, but it will still be accurate when we are all long gone. The adjustable fixtures seem to wear-out. Depending on usage and care it may go from 3 years to 15 years.

Jerry

reply »

#51611

Dedicated or adjustable fixtures for Universal Radial Inserter | 30 August, 2007

> ... talking two-lead LEDS with 2.5mm pitch ...

Yes. That's what we are working with.

> are the LED terminals shape were Square or > the naturally rounded?

Some are round. Some are square. One is U-shaped.

> Due to different insert rotations, you may > wish to do program off-sets per rotation ...

You went over my head with that one. I know how to specify insert location and head rotations and that's it.

reply »

#51612

Dedicated or adjustable fixtures for Universal Radial Inserter | 30 August, 2007

I think you can reach that screen with SH SET command, then do a SET [command name] [value] to change it. Make sure you write down the original values somewhere or do a print screen of your current settings before tweaking them, though.

reply »

#51625

Dedicated or adjustable fixtures for Universal Radial Inserter | 31 August, 2007

Earlier, crashoveride advised:

> > > you may wish to do program off-sets per rotation ...

I responded:

> > You went over my head with that one. ...

Steve Thomas helpfully added:

> ... can reach that screen with SH SET command,

Since I have not yet located a programming manual nor have I had any instructions in programming the inserter, I don't even know what "program off-sets per rotation" are, so going to SH SET wouldn't tell me anything.

Sorry about that. I'm pretty much at the 'see Dick tell the inserter to go to position 08756 02345 and insert a component then see Jane manually insert the mis-inserted part.'

All I have to go on is one example of a program and some information such as 'D C' 'F C' etc.

I also have a three legged "bug" that I use to find the holes in four corners of the board and then it's off to Excel to estimate all the rest of the coordinates.

With our sloppy universal fixture, every time we changed boards, I needed to reprogram whatever new product we were going to run.

This worked well until the stage stopped being able to reproduce a command to go to a single location and had limit errors every time it finished a row.

It's kind of like having the Marx Brothers run the show, but it's a living.

reply »

#51641

Dedicated or adjustable fixtures for Universal Radial Inserter | 4 September, 2007

I could help you with the SET features if I saw them. It's been about 4 years so I don't remember them off the top of my head. What you would do (nutshell) is get your non-rotated insertions dead center, then step through to a rotated insertion until a part is in the head, take the part out, insert the bug, turn off the head air and drop the head to let it rotate and see how far off the bug's leads are from center, then enter the offset. What I don't remember are the characters used for left/right/none rotation (D/C/F?) and which ones are left or right. It seems like left.offset and right.offset values are whet you change in the SET commands but that admittedly is a SWAG.

reply »

#51672

Dedicated or adjustable fixtures for Universal Radial Inserter | 5 September, 2007

> insert the bug, ... let it rotate ... see how far off the bug's leads are from center,

When the head rotates, it rotates about the center (long) lead of the bug. Therefore, the x/y position of that lead does not change as the head rotates.

> ... characters used for left/right/none rotation (D/C/F?)

B C - none & D C - CCW or right & F C - CW or left

reply »

#51681

Dedicated or adjustable fixtures for Universal Radial Inserter | 6 September, 2007

"When the head rotates, it rotates about the center (long) lead of the bug. Therefore, the x/y position of that lead does not change as the head rotates."

Heh-heh. You'd think so, wouldn't you?

Have you observed this with a magnifying glass? What you will find is that in cases where the head has less than optimum maintenance and setups performed, the rotation will be slightly eccentric and that you will see an offset between center, left, and right rotations. The left/right offset set parameters can counter that. So can a good setup on the head, but that does take some additional tooling that I suspect you don't have.

reply »

#51684

Dedicated or adjustable fixtures for Universal Radial Inserter | 6 September, 2007

> > x/y position of that lead does > > not change as the head rotates."

> Heh-heh. You'd think so, wouldn't you? > Have you observed this with a magnifying glass?

Heh-heh yourself. I (think) I know better than to think that it would withstand that sort of test. I *do* assume that the 'unchangability' can be improved by some sort of mechanical voo-doo that we don't know anything about.

Our machine is still down - waiting the parts list from Universal - promised last week. After that, we'll schedule a service call which will last a week.

So much for automation ... we hired a bunch of temps to stuff boards with LEDs for now and the indefinite future.

reply »

PCB machines

Boundary Scan