[m_constrained]

Howdy, I was hoping for some advice on a laser cutter I am working on. I am waffling between using a Synrad 48 series laser or one of these plain CO2 tubes available off Ebay that require a separate HV power supply and cooling method.

I already have a Synrad J48-1 that works beautifully, but I am not sure its going to be powerful enough. I would like to cut 1/4" acrylic and polycarbonate, up to 3/8" balsa wood and engrave in coated metals and glass. I downloaded Synrad's laser power calculator, but I am not sure how accurate that is since most machines use moving optics which lowers the available power. Since the Pana-robo can carry 15 kg without caring in the slightest, I was going to mount the laser vertically directly above the work surface. The only optic is a single ZnSe lens and the laser is located just a few inches from this. There is forced air going over the lens and the work surface to remove cut material. So, I guess my first question is..... For those of you that have laser cutters, am I really going to be limited to 4 inches per minute in 1/4" acrylic using a 10 watt laser mounted as described?

If the answer is even close to yes (I would like to get at least 20" per minute with 1/4" acrylic), I guess I will be going with a larger laser. I don't mind using a 25 watt Synrad, but for that price, it seems as though I can get an 80 watt tube off Ebay. Price is not so big an issue, but I would rather not spend over $4000 for the laser + power supply. With these plain tubes.... Are they going to be as reliable as a Synrad and if it were you, would you buy a plain tube over a Synrad unit? And lastly, where the heck do you buy the power supplies for these tubes. (and please understand, I want to BUY a supply with wiring, not build one. I am quite experienced with electronics, but 16 kV is beyond what I want to mess around with)

If the answer is even close to yes

[KTP]

If I were you I would buy that 60 watt Synrad firestar on ebay for $4750. It was made in 2003 so should provide many years of service, unlike the chinese glass tube lasers. Also since the RF supply is separate, the actual laser head is not much bigger than the 10 watt Synrad, so you coudl still mount it to your gantry/robot.

[m_constrained]

I appreciate the advice. I think his price is rather solid at $4750 though which is above what I want to spend. As far as size goes, it is perfect, and the head weighs just a couple pounds more than the entire 48-2 laser. I take it from your suggestion that a 25 watt laser is probably not up to the task of cutting 1/4" acrylic at at least 20 IPM?

[KTP]

A hot 25 watt laser (most Synrads actually do 30-35 watts for several years) should cut 1/4" acrylic at 20IPM or maybe just a bit slower. I am always a fan of the more-power-is-better club though. Kind of like that milling machine that just needs x inches more travel to do the job you want...

[pyroplotter]

Small world - I bought their last T60 laser a few weeks ago. I also use a J48-1 mounted on a gantry and will be putting the T60 head on the gantry in a couple of weeks. I'll let you know my results if you're interested.

When I got the laser and tested it I found it melts cinder block quite nicely without a lens and expect to get good acrylic cutting speeds. Power consumption at full power was 33 amps @ 30 volts. I got one of the big HP6268 supplies on eBay and that runs off 240V to power the RF module.

My table doesn't run well above 20 ipm while writing and I was finding I had to do 4 to 6 repeats in wood and museum board with the J48-1 for some of my patterns so I got the higher power laser. I also like the little laser. http://www.pyroplotter.com

Another thing I did was buy a Cut Quality Enhancer from Laser Mechanisms. I was finding that when I cut and engraved signs without the lens I got directional inconsistencies ( kerfing ) from the vertical polarized beam. With the CQE that's eliminated and since I'm getting into smaller items like jewelry I wanted better beam control. Not cheap though.

Wil

[Laser Doctor]

Howdy, I was hoping for some advice on a laser cutter I am working on. I am waffling between using a Synrad 48 series laser or one of these plain CO2 tubes available off Ebay that require a separate HV power supply and cooling method.

I already have a Synrad J48-1 that works beautifully, but I am not sure its going to be powerful enough. I would like to cut 1/4" acrylic and polycarbonate, up to 3/8" balsa wood and engrave in coated metals and glass. I downloaded Synrad's laser power calculator, but I am not sure how accurate that is since most machines use moving optics which lowers the available power. Since the Pana-robo can carry 15 kg without caring in the slightest, I was going to mount the laser vertically directly above the work surface. The only optic is a single ZnSe lens and the laser is located just a few inches from this. There is forced air going over the lens and the work surface to remove cut material. So, I guess my first question is..... For those of you that have laser cutters, am I really going to be limited to 4 inches per minute in 1/4" acrylic using a 10 watt laser mounted as described?

If the answer is even close to yes (I would like to get at least 20" per minute with 1/4" acrylic), I guess I will be going with a larger laser. I don't mind using a 25 watt Synrad, but for that price, it seems as though I can get an 80 watt tube off Ebay. Price is not so big an issue, but I would rather not spend over $4000 for the laser + power supply. With these plain tubes.... Are they going to be as reliable as a Synrad and if it were you, would you buy a plain tube over a Synrad unit? And lastly, where the heck do you buy the power supplies for these tubes. (and please understand, I want to BUY a supply with wiring, not build one. I am quite experienced with electronics, but 16 kV is beyond what I want to mess around with)

If the answer is even close to yes

I have extensive experience in this area. Synrad builds a very good laser. The 48-1 only requires a 30 to 32 VDC input to run the laser. Glass tubes require very high voltage. Fortunately they are only running @ 50 MA DC max. So don't worry you won't kill yourself, but you will get quite a tingle if you touch the anode when one. For 1/4" acrylic I recommend a 50 watt unit to be safe. 25-watts just doesn't cut it. No pun inteneded.

Be carefull purchasing lasers on the internet. Lots of junk our there. You can always send your tube to Photovac Laser Corp, in Grove City Ohio to have it checked out. These guys only work on RF and DC tubes. For a couple hundred bucks they will tell you if it's worth it or not.

Plain glass tubes and RF tubes are quite different. The biggest difference is electrode contamination. With DC tubes the electrodes and gas directly contact each other when the HV is applied. In RF tubes the gas bounces betweent the RF electrical platers and doesn't come in contact with the plates. This is one of the main reasons the gas lasts so much longer in a an RF tube >5000HRS. DC tubes <1000HRS.

[MonoNeuron]

To laser Doctor,
Welcome to our little corner of the web. I probably speak for all of the laser posters here by welcoming any of your comments whether good or bad because there isn't a lot of information out there that someone can learn about lasers.
It's nice to have someone come aboard with a wealth of extensive knowledge and willing to share it.
I live in the outback miles from nowhere in Australia and this is my first foray into laser technology and I find it so damned intriguing and fascinating and it seemed a logical step up from a CNC gantry router. The web is my only source of information as the Public Library has only old books on Ruby lasers and no one else in town has had anything to do with lasers except the pointer type. I am not rich so my budget is very low and glass tube lasers will be my method of choice until the lotto comes in.
If I ever get my laser up and running then it will complement my routers and also give my little woman another outlet for her Scrap booking shop (which she is getting very impatient for).
One thing I would like to ask you though is how to wire up the Chinese laser power supplies. The one with the 3 AC in terminals and 6 input terminals to control the laser with a Potentiometer or through TTL
1 = TTL High
2 = TTL Low
3 = Protection Port
4 = Gnd
5 = DAC power control
6 = DAC power control

would you have a schematic in English that I could use with LinkMotion to connect the computer to it using TTL control for the modulation?
There is another thread here that has pin outs but I need to have someone explain which port does what so I don't fry an $800 power supply.
I don't seem to get that the TTL signal goes into pin 1 BUT the power control signal goes into pin 5 or 6
LinkMotion sets pin 14 on the parallel port for the laser modulation and can't be changed.

Any body reading this thread is also welcome to jump in especially ones that have one working. I would also like to start a new thread with "Laser Power Supply" that people can search for when wiring one of these things up so it may be found easily instead of being buried 12 pages into a thread that takes weeks to find.
Paul the Admin ????? can you help as you have already been through all this and have yours up and running.
Richard.

[Laser Doctor]

It appears you can control the power supply in two ways. The TTL signal is typically greater than 3.2VDC from a pulse generator. Pin 1 being the high and pin 2 being low. The DAC control typically uses a 2 k ohm potentiometer. In not sure which pin 5 or 6 is your typicall 5 VDC drive voltage. Use a volt meter to indentify which pin is 5 volts. Connect one side of the pot to the 5 volts. The other pin (swinger arm) (middle) corresponds to the output D.C. current. The remain tab of the pot will reference ground.

Good Luck

The Laser Doctor

[NSchlee]

Is there anybody that recharges Synrad tubes, besides Synrad?

Thanks,
Neal

[MonoNeuron]

Laser Guy
Thanks for the info. I was still a little unsure but I connected the emergency port to ground and the Hi to the ground also through a switch and it fired. I have now cut a series of dots and a line in some cardboard. I am having trouble setting up LinkMotion and Dhiren Shah from Solustan suggests I upgrade the computer I am using as it is a bit slow (500MHz with 300 Meg ram). I am upgrading to 3.2 Gig chip with 1 gig RAM which should do the trick. Steppers REALLY sing when run through Linkmotion.
Rich

PS NSCHlee
Laser Guy says this from another forum
" I would recommend sending your tube to Photovac Laser in Grove City, Ohio "

So check it on out !

[Laser Doctor]

Is there anybody that recharges Synrad tubes, besides Synrad?

Thanks,
Neal

Neal:

Try Photovac Laser. Web: www.photovaclaser.com

The Laser Doctor

[NSchlee]

Thanks Doc,

Christopher @ Photovac says $1200 to recharge the 57-1 100 watt Synrad, seems very reasonable as Synrad quoted $4,000 2 years ago.

Neal

[BUSA BOY]

Hi (((Im new))) I hope im in the right place.
Can anyone help
I have a laser that keeps loosing its mind... the control box that counts the steps looses count and does what I have named crossing over. imagine cutting out 2 square objects that are right next to each other and do not overlap on the drawing but when the laser cuts it out they overlap!!! it is very frustrating. I have checked the motion screws and backlash nut are not loose, I have put a ground rod in next to the machine and grounded it, I grounded everything on the machine. I don't know what else to try!!!
Can anyone help?

[KTP]

I think you need to disable the little thing below the other thing, then power up the widget thing near the back and upload the software patch from that website.

Specifics help, don't they?

So what is the name/brand of your laser engraver?

[BUSA BOY]

Like I said, im new at this.
thank you for replying. the laser is a 50 watt Synrad but it is a home made x and y axis with 1 stepper motor on each axis and a kern control board inside the pc. it cuts 24X24 on each axis but it looses count somehow and does the weird overlap cutting. I am not too technical but I should be able to answer any more questions, I do appreciate your help. thank you

[MacGyver]

If your software allows you to set the number of steps/s, try lowering the value... you may be pushing the hardware's ability to keep up.

[BUSA BOY]

I think you need to disable the little thing below the other thing, then power up the widget thing near the back and upload the software patch from that website.

Specifics help, don't they?

So what is the name/brand of your laser engraver?

Like I said, im new at this.
thank you for replying. the laser is a 50 watt Synrad but it is a home made x and y axis with 1 stepper motor on each axis and a kern control board inside the pc. it cuts 24X24 on each axis but it looses count somehow and does the weird overlap cutting. I am not too technical but I should be able to answer any more questions, I do appreciate your help. thank you

[BUSA BOY]

If your software allows you to set the number of steps/s, try lowering the value... you may be pushing the hardware's ability to keep up.

thank you for replying. I forgot to mention that sometimes it works without flaw and then for what appears to be no reason it overlaps on the cutting again. I am not too technical but I should be able to answer any more questions, I do appreciate your help. thank you

[KTP]

If it works sometimes but not others, then possibly the stepper motors are losing steps on direction change. Try lowering the acceleration values if that is even possible with your controller. Is there any binding anywhere on the machine when you move it by hand? Does the problem seem to happen only in certain spots on the 24 x 24 inch cutting area? Is it belt drive on both axis?

[MonoNeuron]

What software are you using? I don't think it is the software though as I had a similar problem with my setup but I had servos and not steppers. I had 1 raster file "printed" twice with a 100 thou shift (like a shadow) and an outline around the both at twice the size. Really weird. vector cut would always come back to the start but circles wouldn't join up by the 100 thou shift. It turned out to be the drives somehow. I used Geckos and even sent them back for testing and they tested OK but still had the shift when cutting or engraving. It may have been the tuning of the drives but it doesn't explain your problem with the steppers. Make sure you have selected the step ratio correctly ie 8 micro steps or 10 micro steps etc and use the same settings in your software program. Check all the pins in your parallel cable to make sure they all have the same resistance (I had that problem once and the drive couldn't make up it's mind whether to go high or low, at random)
You wouldn't believe the weird things that can go wrong. 2 weeks ago I fitted a stainless steel top to my laser then the computer running it decided to stop straight after. 5 days later and another $300 I finally got it to work. I now use a UPS (uninterruptible power supply) on ALL my equipment to filter the power going into all my CNC machines. We get a lot of brown outs and surges here. It turned out to be a faulty USB port on the motherboard which stopped it from powering up.
I hope I have been some help to you but just stick to it and check even the simplest of things and you may just find it.
Rich.