Uninterruptable Power Supply UPS for the laser

[Mark Ross]

We have run into an issue with our Epilog 36EXT 45 Watt laser, where it decides to wander off every once in a while. By once in a while, it might occur one time in a month, then go a couple of months with no problems, then do it twice in a week.

It doesn't wander off only in the X or only in the Y, and the laser keeps firing so we end up with scrap material. I talked to the guys at Epilog and they said it sounds like some sort of data corruption. BTW, yeah we keep the encoder strip clean and do normal maintenance.

Since it doesn't happen when we send the file (doesn't happen the first time we run the job) and it doesn't always happen after running the same file X amount of times from hitting go on the front panel, they think it is happening when the machine is writing the file from the section of memory used to store jobs to the work area for the current job.

We know it isn't the artwork files as these are locked down and can't be changed. It happens when we vector cut (we don't raster much).

The thought is to first buy a UPS and put that on the input to the machine to see if the problem goes away. We are thinking maybe the building compressor, one of our chop saws or who knows what might be causing a power glitch.

They said get a standard UPS that you would use on a computer, a 15 Amp unit. However, a 15 amp unit is almost 500 bucks and I don't think these things need anywhere near that amount.

Has anyone sized as UPS for an Epilog 36EXT running at 45 watts or higher? What works well? Thanks for the input.

[paul mott]

Mark,

I think a mains filter (to remove any possible electrical noise spikes) may be a better approach than a UPS - certainly a lot cheaper.

Paul.

[Greg Bednar]

I think if I remember correctly in talking with Epilog - look for a 1KW and you should be safe - A little pricey. I just use good filtering here.

[Richard Rumancik]

If Epilog thinks the problem is a result of copying files internally, have they also talked about replacing memory? Are the source and destination memory chips/sticks both replaceable? If so, this might be something to consider . . .

[John Noell]

Unfortunately, most UPSs do not regulate the voltage unless there is an extreme shift. Yes, if the power fails they will cut in "instantly." If the voltage gets too high they usually cut in only when it gets REALLY high (~300V in some cases). Check the specs carefully. The high end ($$$) UPSs do both volatage regulation and battery back-up. After a lot of research (and some mis-direction by Epilog on the power needs), I concluded that voltage stabilization is more important. That is why I use an APC automatic voltage regulator.

[Richard Rumancik]

Just to clarify - I certainly did not intend to suggest that you drop the idea of some kind of surge protection. I am all for a surge protector; in this business you get what you pay for. A $10 power strip won't cut it. There has been some prior discussion on surge suppression so perhaps do a search on surge suppressor, UPS, TVSS (transient voltage surge suppressor), voltage regulator etc and see what you find. Various people have different solutions - like buying insurance, it depends on what you can afford, your risk tolerance, potential loss, etc.

There are often good deals on eBay. Search "UPS" and "rack". I think you will have better luck finding a rack-mounted unit that meets the needs. If the batteries are old you may need to replace them for say $150 but that is not really a bad approach. A new one might cost between $500-1500 depending on wattage and features.

What struck me is that you were addressing what I thought sounded like a memory or a board-design problem by adding surge protection. If Epilog really thinks memory is causing it, then I would say you have either bad memory or there is a problem with the board design. As much as I believe in proper power conditioning, I am not convinced that it will correct something that is happening on the mainboard.

Is there a separate power supply in this unit for the mainboard or does it tap off the main supply (shared by the laser tube)?

[Robert Walters]

If you hit surplus electronic places you can find APC SU2200RM3U UPS really cheap and even free (excluding batteries). Might even check classifieds and craigslist.

They'll sit on shelves for a very long time as they're too heavy to ship. You could haggle over the price.
They might be happy just to get the shelf space back.

http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=su2200rm3u&tab=documentation

They use 8x 12v@8AH gel cell batteries which can be expensive, you *might* be able to use alternative batteries (deep cycle?) externally.

This particular UPS will also condition the power; so if you get a brown out (low voltage condition), it'll compensate using battery power.

Do you have a history of dirty electricity? lights dim? etc.

It might be cheaper to buy a meter and run for 72 hours and see what you have, then go from there.

[Mark Ross]

Sorry, I didn't post enough information. Epilog would be more than happy to replace the motherboard for $1,000 but if two months goes by and the problem happens again (meaning it wasnt the motherboard) they are not willing to refund the money. The issue is so random and we cannot replicate it that at this point we are going to live with the scrap. If it gets really bad, then we will look at what we can do (i want a new laser...that one that would allow unlimited surface area. That would be sweet. Thanks for the replies, if we ever do find out what causes it to go all derp de derp on us from time to time, I will post so others will know.

[Robert Walters]

Mark,

Servo motors don't just randomly wander off.
If you haven't already, you might take a day or two and break the machine down and to a PM on it.

Check all the bearings, belts, cables, wiring, loose screws, alignment, lube, etc. Inspect/clean EVERYTHING.

When the wandering happens...
Are you running the machine heavily?
Is it a long job?
Is the weather cold/damp hot/dry?
Is it a heavy smoke producing job?
Is it a heavy dust producing job?
Do you have enough exhaust power (CFM/SP)?
Is the exhaust ducts clean, clear, and unobstructed?
Are you using air assist?
Is there other equipment in your shop being used at the same time?
Have you grabbed a meter and tested the electrical power?
Do you have any issue with other equipment in you shop?

[Richard Rumancik]

Mark, is all the memory on the board soldered in or is it replaceable? If there are pluggable memory chips I'd at least try it before replacing the mainboard.

The reason I asked whether this unit has a separate power supply for the main board is because it could be possible to add extra filtering and surge suppression in front of that supply at low cost, since it will be a low-wattage supply. Although power-line conditioning on the entire input is good, you could add extra conditioning to the mainboard supply at low cost.

Your power utility company might be able to give some suggestions. Perhaps they will lend you an event recorder that can check power line quality. They also can give good advise on conditioners and UPS equipment. (They might not even charge for it.)

Have you considered the possibility that it is caused by static discharges (ESD)? You might want to check the integrity of your building ground and the laser enclosure ground. Perhaps a special ground would be in order. Ask Epilog for advise or consult with an EE friend who might be able to give you some suggestions. Also, if you are using a vinyl hose for laser exhaust it can be a source for static (moving air in a plastic tube). If there is a spiral wire inside it, ground the wire to the metal ducting and also to earth ground. If no wire, perhaps you could spiral wrap it with bare copper wire and ground it.

Does the problem happen when nobody is around? Or does it happen when someone approaches the laser and is potentially charged up? If there is no easy ground path for any static it can go into the electronics. Maybe a conductive mat would help. Or some way to discharge people before they get to the laser panel.

Keep your eyes open to things that might be causing ESD - such as peeling plastic film off of sheet plastic or opening plastic bags. I know it's hard to find a pattern when it happens infrequently but you need to try to determine if there was an event that might have triggered a malfunction.

I would not give up to quickly. If you know an EE invite him (or her) over and maybe they can come up with a few ideas.

[James Terry]

On the topic of UPS, I use an old ferro-resonant (http://en.wikipedia.org/wiki/Uninterruptible_power_supply#Ferro-resonant) UPS system which is online always and actually filters the output for you. The transformers are huge and can generate some heat but I think it's worth it. You can find them second hand on Craigslist (http://www.google.com/search?q=site%3Acraigslist.org+ferrups&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a) for very cheap. And you can easily modify them to use an external battery pack of easy to maintain deep cycle marine batteries. I hate those sealed lead acid batteries. They are useless. I currently use a 5.3kva unit that sources on 240 and outputs 240 and 120. I paid $200 for it and it is probably worth triple that in copper alone.

http://www.sugarglider.com/glidergossip/Photos/2571/DSC02451.JPG