Chinese Lasers-Rodney Gold And George M. Perzel please help!!!!

[Brian Martin Pennsylvania]

Good Day,
I’m in the market for a flatbed laser, preferably Chinese since that’s what I can afford right now. I came across three Chinese companies, Redsail, Iehk, and Shenhui. Redsail and Iehk carry the 48” x 96” flatbed laser but Shenhui does not. This is what I want to accomplish. I’m cutting 18”x 5/8” strips out of a 4’ x 8’ piece of High Impact Polystyrene. My goal is to place the sheet on the laser bed, press a button and let the laser do its thing. I have a lot of questions about Chinese lasers so if anyone has one please put your two cents in.
Here are some of my questions.------Rodney Gold and George M. Perzel please help me out!!!!!!!!!!


What is autofocus.
Are U.S. parts interchangeable with Chinese. (Lens, Mirrors, Tubes)
Would there be a problem running these lasers continuously during an 8 hour day. I read some comments on here about upgrading the chiller unit from Redsail.
For the people that own Chinese laser cutters, what are the lead/delivery times from China.
Are the wattages the same here as in China. For instance my material cuts flawlessly on a U.S. 150w laser. Should I expect the same from a Chinese laser.
If anyone has any upgrades they made themselves on the machine please feel free to talk about them.

[Talley Boatwright]

I can answer a few of your questions. I have done many imports in the past. Personally, I would not consider Redsail at all.
I run three type of lasers, CamTech L20, Epilog Legend 36EXT 60 watt, and G. Weike LG3040 40/50 watt.
Two RF sealed C02...Synrad...Coherent and one glass tube. The sealed tubes are more reliable than glass tube. However, more expensive. Power is not the same, even though rated same power. Glass tubes have be sealed properly in order for the gas not to leak. Importing also can be tricky if no research is done. I did my own importing and it tales about 35 days roughly. That is considering customs and railroad. Feel free to ask me any questions if need.

[Brian Martin Pennsylvania]

Thank you Talley. What's your recommendation for a Chinese flatbed laser that can handle 48" x 96" material. Are sealed C02 laser tubes universal and are there any modifications I can make to be confident that I can get 150watts out of the laser to cut my material. BTW I am very handy with tools (welding, pneumatics and fabrication) so heavily modifying is not a problem.

[Rodne Gold]

Good Day,
I’m in the market for a flatbed laser, preferably Chinese since that’s what I can afford right now. I came across three Chinese companies, Redsail, Iehk, and Shenhui. Redsail and Iehk carry the 48” x 96” flatbed laser but Shenhui does not. This is what I want to accomplish. I’m cutting 18”x 5/8” strips out of a 4’ x 8’ piece of High Impact Polystyrene. My goal is to place the sheet on the laser bed, press a button and let the laser do its thing. I have a lot of questions about Chinese lasers so if anyone has one please put your two cents in.
Here are some of my questions.------Rodney Gold and George M. Perzel please help me out!!!!!!!!!!


What is autofocus



Are U.S. parts interchangeable with Chinese. (Lens, Mirrors, Tubes)
Would there be a problem running these lasers continuously during an 8 hour day. I read some comments on here about upgrading the chiller unit from Redsail.
For the people that own Chinese laser cutters, what are the lead/delivery times from China.
Are the wattages the same here as in China. For instance my material cuts flawlessly on a U.S. 150w laser. Should I expect the same from a Chinese laser.
If anyone has any upgrades they made themselves on the machine please feel free to talk about them.



Autofocus is a means where the laser focuses itself , often both inacurate and troublesome .. don't bother with it.

Any lens and mirror can be used with the machines , US or not. Sealed RF and glass Tubes as well , however replacing your glass tube with a sealed CO2 RF will be PRICEY
Motors and stepper drivers etc can be interchanged , but motherboards probably not. Price of spares for a chinese machine is real cheap , adding a raft of them to your laser if you bring one in will not cost a lot

I run mine 8 hrs a day , 5/7 and have had 2 years use (almost) ..just replaced one of my 60w glass tubes at a cost of $170 , got at least a years use out of it..it didnt fail completely but was down on power.


Lead times depend on whether yours is a custom build or something unusual or one of their stock units . Have a look at the sticky at the top , look at the despatches from china link and you can see the scale of the chinese factory I went to..confidence inspiring (Shenui)
I would allow 2 months from order/deposit to your door , 3-4 weeks for the custom build..3-5 weeks for shipping and clearing. Putting pressure on the mnfgrs to deliver sooner will get you a shoddy product. I understand the angst of paying a producer a zillion miles away and waiting for em to ship etc..

No , you wont get the same cut from a 150w chinese laser in terms of speed and perhaps cut width or quality , the beam shape is not as good and neither are the lenses you get supplied , you would have to cut slower HOWEVER at 1/5th of the cost , you can afford to buy 2 and exceed production of 1x 150w mainstream machine. Quality will be very acceptable , its not like it wont cut at all or be real bad.

I wouldn't suggest upgrading anything as a DIY unless there is an issue..buy one and run it

If your machine is expensive EX china , like $15-25k , why not fly over and go visit ..interesting place and the cost will soon be overwhelmed by your piece of mind , might save you from making an expensive mistake. Take your material with and ask em to run tests , most co's will oblige..face to face is big in china , if you do go , they will respect you and realise they can't dicker with you.

I was real impressed with Shenhui , even if they don't carry a machine that size (I'm not too sure any of the others will have it in stock for immediate shipping...most tend to build to order) , I saw plenty flatbeds there, *they* build to order , workmanship on my machines is very good.

[George M. Perzel]

Brian;
Rodne pretty much answered your questions. I would be leery of trying to cut a 4x8 sheet on any laser much less a chinese one as focus over that area will be very difficult to maintain. Also your machinje will be huge a weigh a ton-can't you cut your sheets into 32 x48 size and use a smaller machine? I am close to you up here in NY-call if you want to discuss anything.
Best Regards,
George
Laserarts
585-924-4519

[Sam Larter]

Brian,

I've been looking for a Chinese laser for a while and have read through the last two years of posts here and there is another Chinese Laser manufacturer that makes a machine large enough for your purpose.

They are G. Weike and they have received many positive reviews by people here.

They have a laser cutter with a bed size of 1300mm x 2500mm listed here: http://www.wklaser.com/product/11_194.html that can be ordered with up to a 200W laser tube. Check them out and see it they can help. From what I've read on here and other websites is that the two best Chinese manufacturers are Shenhui and G. Weike. Most of the U.S. sold and supported machines are made by these two companies.

Good luck,

Sam

[Talley Boatwright]

Thank you Talley. What's your recommendation for a Chinese flatbed laser that can handle 48" x 96" material. Are sealed C02 laser tubes universal and are there any modifications I can make to be confident that I can get 150watts out of the laser to cut my material. BTW I am very handy with tools (welding, pneumatics and fabrication) so heavily modifying is not a problem.
With my experience Jinan G. Weike is a good company to deal with. Sealed C02 laser tubes are universal; however, the tubes cost more than buying a complete machine depending on the wattage. Plus you have to purchase the power supply, control module etc.

As far as Auto focus goes, I totally disagree with Rodne about inaccurate and troublesome. Auto-focus can be tweaked for optimal focusing. If you are running the same flat and level material...yes, it is best to manual focus because auto-focus does slow up production by 20 seconds each time at the most.

May I ask, what type of work are you planning to do with 150 watts of power? Kern Laser offer flatbed lasers with plenty of power but costly.

[Brian Martin Pennsylvania]

252296Talley,
I will be running the same flat and level surface, even the material won't change at all. The only type of work that will be done with the laser would be cutting 18" x 5/8" x 3/16" strips made out of high impact polystyrene. (HIPS) I actually contacted Kern Lasers and sent them a sample of my HIPS and their laser cuts the material beautifully on a 150w laser so I was guestimating that a 150w lasers would be the optimal choice. Their lasers however are a little bit out of my price range. 100,000.00+... But their customer service is amazing.

[Brian Martin Pennsylvania]

"No , you wont get the same cut from a 150w chinese laser in terms of speed and perhaps cut width or quality , the beam shape is not as good and neither are the lenses you get supplied , you would have to cut slower HOWEVER at 1/5th of the cost , you can afford to buy 2 and exceed production of 1x 150w mainstream machine. Quality will be very acceptable , its not like it wont cut at all or be real bad"

Thanks Rodne for your input and advice. Speed right now isn't a big concern compared to quality. Would I get a better cut if I bought American lenses and perhaps a sealed U.S. tube. The picture I included is my material cut on an U.S. Kern 150w laser. I'm hoping to get a similar cut on a Chinese laser. The material is 3/16" high impact polystyrene.
252298

[Talley Boatwright]

Did Kern give you some settings that your material was cut at? 150 watts is a lot for a laser. I guess I need to do some research on this material. What application is it used for?
"No , you wont get the same cut from a 150w chinese laser in terms of speed and perhaps cut width or quality , the beam shape is not as good and neither are the lenses you get supplied , you would have to cut slower HOWEVER at 1/5th of the cost , you can afford to buy 2 and exceed production of 1x 150w mainstream machine. Quality will be very acceptable , its not like it wont cut at all or be real bad"

Thanks Rodne for your input and advice. Speed right now isn't a big concern compared to quality. Would I get a better cut if I bought American lenses and perhaps a sealed U.S. tube. The picture I included is my material cut on an U.S. Kern 150w laser. I'm hoping to get a similar cut on a Chinese laser. The material is 3/16" high impact polystyrene.
252298

[Rich Harman]

I have compared pieces cut by a 75W Epilog, 120W Universal, and my 80W Shenhui.

Don't know about the kerf width but I cannot tell any difference in quality of cut.

[Brian Martin Pennsylvania]

Thank you George for your input. Can you explain to me what you mean that the focus would be hard to maintain over that area, I'm new to lasers so I'm dealing with the learning curve. I can cut the sheets down but I would then loose material. I can get about 341 pieces out of a 4' x 8' sheet but if i cut those pieces down I would loose material. (I'm planning to mass produce these 18" x 5/8" x 3/16" strips of High Impact Polystyrene)

[Brian Martin Pennsylvania]

Yes the settings that Kern gave was 1" per second at 100% power at 150w. The HIPS material is being used for the body of a magnetic pickup tool. Its a thermoforming plastic if that helps.

[Rich Harman]

Three ways I can think of that it will "lose focus".

1) 48 x 96 is a very large area to keep absolutely flat. Even with a perfectly flat table the material can bow or warp so you may need a way to hold it down - such as a vacuum table.

2) All laser beams diverge. That means that if the beam is the diameter of a pencil when it leaves the laser tube it may be the diameter of a hot dog by the time it gets to the furthest point on the table. For example my 35" x 55" laser has a beam path that is about 120", at its furthest point the diameter is about 10mm. To compensate I cut things a little slower in the far corner of the table. This problem can be minimized by using a beam expander but then you lose depth of field. However, a machine as large as you are contemplating will probably have the laser tube mounted to the gantry so the length of the beam path may be short enough (probably less than 80") so that this effect may not be an issue.

3) The longer the beam path, the more sensitive the alignment. The tiniest bit of misalignment will result in a great loss of power when the cutting point is furthest from the laser source. The same amount of misalignment would be completely undectable on a machine with a shorter beam path.

A machine such as mine (most larger Chinese machines I think) has pass through capability. You could get a smaller machine and setup a feed system to move the material through the machine. The software has provisions for this but you would need to construct your own feed system.

I am sure that there are people here that would be willing to make some test cuts for you on their machines. Probably a good idea since you know exactly what you need to use the machine for.

[Rodne Gold]

Yes, if you changed to a Sealed RF synrad or the like tube and used quality lenses , you would get the same cut, HOWEVER it is a snap to do so , most of the chinese motherboards have provision for PWM control , and replacing a lens is , well replacing a lens.
What I would do is try a machine with a glass tube etc first, IF it doesn't work , then go RF tube (you would have to change the laser power supply and tube)
Before going RF tube tho , I would just change to quality lenses. I might have to do a retraction to the folk here ..cos I was convinced via trying, that the cheaper chinese lenses were as good as the more expensive optics , well we changed out a cheap lens in one of my machines for a slightly battered expensive one from my mainstream lasers and it does cut quite a lot better....
George is saying that maintaining complete flatness on huge bed sizes is VERY difficult. At the very least , you would have to have a proper floor/bed for the machine as any small twist that results from an uneven floor (even if you level the machine) can translate to a coupla mm on the bed. Added to that , even transport can twist the bed outa shape. I don't think the laser mnfgrs in China are able to construct a huge machine with such precision..BUT its not a major issue , you could construct a sub bed and clock that up.....

[Rich Harman]

If you are running the same flat and level material...yes, it is best to manual focus because auto-focus does slow up production by 20 seconds each time at the most.


Autofocus on my machine means - when I want to focus, I push a button telling it to do so. It does not happen automatically each time a job is run.

I've stopped using autofocus primarily because much of the time the material I am cutting has a bit of warp to it. Since I have to hold the sheet down anyway when focusing I just use a gage. After it is focused I use the laser to draw rectangles so that I know where I can place magnets to hold the material flat.

If I were always cutting nice flat things then I would still be using the autofocus.

[Dan Hintz]

even transport can twist the bed outa shape.

Glad you mentioned that, Rodney... the bigger the machine, the more man-handling required, and it's tough to keep a machine that large from warping while still keeping it relatively light. One good bang on the dock with a forklift (or even lowered at an angle), you could have a twist that may never come out with just leveling feet.

[Brian Martin Pennsylvania]

Rich,
Thank you for putting this in perspective for me. So if I'm understanding you correctly if the laser tube its mounted in the gantry of the flat bed laser, then the laser beam should be relatively the same throughout the whole sheet since the motor will be moving the gantry on the x,y axis. The only thing I would have to take into consideration is the 4' x 8' HIPS warping, (Which is does) and causing the laser to loose focus because of the discrepancy in material height. One of the ideas that I read on this site is going to harbor freight and buying magnets to hold the material down. The machines with the pass through capability is a great idea as well, I'm doing do more research on them as well.

[Brian Martin Pennsylvania]

One thing I forgot to mention. I was planning to cut the the strips of High Impact Polystyrene back to back with no space between cuts so I could keep my material waste low. A 4' x 8' sheet would yield about 341 pieces if there was no space left between cuts. Would there be a problem with this? I also calculated that the laser would use up 1/16 of material. For instance in my calculation I added 1/16 to 5/8 to accommodate for material lost. Any suggestions????

[Rodne Gold]

Just as a matter of interest , why do you want a laser to cut these strips? What about a panel saw or a cnc type router that wont put so much heat into the material?
http://www.cutlasercut.com/laser-cutting-materials-laser-engraving-materials/clear-hips

[Brian Martin Pennsylvania]

Just as a matter of interest , why do you want a laser to cut these strips? What about a panel saw or a cnc type router that wont put so much heat into the material?
http://www.cutlasercut.com/laser-cutting-materials-laser-engraving-materials/clear-hips

A panel saw actually melts the plastic way too much on the edges and produces hot clumps of material that ends up on the strips. A couple months ago we were looking into a cnc router but the only set back is the clamping method and we would have to remove the pieces one at a time as the bit finished them. We also checked out water jet machines but couldn't find any in our price range. Today we had the idea of cutting the 4' x 8' sheets down for a smaller machine but then realized that the panel saw melted the plastic so much on the edge that they won't lay flat, which would cause the laser to loose focus. It's an ongoing process to find a suitable machine. Thanks Rodney for all of your help.

[Dan Hintz]

A couple months ago we were looking into a cnc router but the only set back is the clamping method and we would have to remove the pieces one at a time as the bit finished them.

Are you leaving in bridges / tabs?

[Rich Harman]

One of the ideas that I read on this site is going to harbor freight and buying magnets to hold the material down.

I use pairs of .5" x .5" x 2" grade 42 neodymium magnets for hold downs. You won't find those at Harbor Freight. They are very strong and have the added benefit of being low enough that the laser head cannot hit them.

They are about five bucks a piece at magnets4less.

However, it sounds like you will not have any clear space to place any magnets if your strips are only 5/8" wide.

[Ross Moshinsky]

A panel saw actually melts the plastic way too much on the edges and produces hot clumps of material that ends up on the strips. A couple months ago we were looking into a cnc router but the only set back is the clamping method and we would have to remove the pieces one at a time as the bit finished them. We also checked out water jet machines but couldn't find any in our price range. Today we had the idea of cutting the 4' x 8' sheets down for a smaller machine but then realized that the panel saw melted the plastic so much on the edge that they won't lay flat, which would cause the laser to loose focus. It's an ongoing process to find a suitable machine. Thanks Rodney for all of your help.

Vacuum table for the CNC machine?

[Brian Martin Pennsylvania]

We wern't planning to leave tabs, we were figuring on cutting the pieces back to back. This way the only wasted material would be that of drill bit itself.

[Brian Martin Pennsylvania]

Would a vacuum table hold all the pieces down in place if we are not leaving room for tabs or bridges?

[Jerome Stanek]

For small pieces I use a pressure foot on my router. Could you use one on a laser also.

[Ross Moshinsky]

Would a vacuum table hold all the pieces down in place if we are not leaving room for tabs or bridges?

18" x 5/8" strips should have no problem being held down by a good vacuum table.

I don't think a laser is the wrong way to go about things though. There are people in the US with Chinese machines with 130-150W tubes that I'm sure could run samples for you.

[Brian Martin Pennsylvania]

For the vacuum table, would it be possible to build my own. I'm extremely good with tools and pneumatics is one of my specialties.

[Rich Harman]

For the vacuum table, would it be possible to build my own. I'm extremely good with tools and pneumatics is one of my specialties.

Absolutely. You don't need a complex or very powerful one like you would need with a router table.

[Ross Moshinsky]

For the vacuum table, would it be possible to build my own. I'm extremely good with tools and pneumatics is one of my specialties.

Visit the ShopBot forum. There are a few very reasonably priced vacuum table setups available.

If you're serious about going the CNC route, I'd suggest you possibly look into DIY kits. They'd probably be very suitable for your need. CNCRouterParts and Joe's CNC have the two most popular kits. Both are more than capable of doing what you want and you could probably get the whole job done for around $10,000 including a vacuum table and software.

If I were in your shoes, I'd contact someone in the US with a 130-150W Chinese machine and ask them to cut some samples for you. I'd also contact someone with a CNC Router willing to cut you some samples. See if anyone is able to achieve the quality you want. One thing is certain, the CNC Router will be MUCH faster. You should be able to achieve cuts at over 150 ipm easily while a laser I can't imagine cutting at more than 25ipm.

EDIT: I may be inaccurate with my 150ipm statement. Based on a bit more research the speed probably will be much lower than this.

[Rodne Gold]

I think your problem will be heat , using our 80w , we cut up to 2mm HIPS (the clear one) , but mainly 1mm (we use it as a cheap but stiff backing for some of our domed products) and it warps a lot , no use using magnets as you can only hold the edges really and not where it cuts. The only reason it melts using a panel saw is that the wrong blade was used , had the same problem slicing up sheets of plastic on our table saw and buying the right blade made it go away.

[Brian Martin Pennsylvania]

Thank you Ross. For the CNC router what size bit do you recommend to use. We actually had the prototype strip made on a cnc router. The only set back was the router used a 1/2" bit will almost doubles the prices of the strips.

[Brian Martin Pennsylvania]

Thanks Rodne. May I ask what tooth blade you were using. We were using a 10 inch 200 tooth blade. I believe it said specifically for laminate floor.

[Brian Martin Pennsylvania]

Visit the ShopBot forum. There are a few very reasonably priced vacuum table setups available.

If you're serious about going the CNC route, I'd suggest you possibly look into DIY kits. They'd probably be very suitable for your need. CNCRouterParts and Joe's CNC have the two most popular kits. Both are more than capable of doing what you want and you could probably get the whole job done for around $10,000 including a vacuum table and software.

If I were in your shoes, I'd contact someone in the US with a 130-150W Chinese machine and ask them to cut some samples for you. I'd also contact someone with a CNC Router willing to cut you some samples. See if anyone is able to achieve the quality you want. One thing is certain, the CNC Router will be MUCH faster. You should be able to achieve cuts at over 150 ipm easily while a laser I can't imagine cutting at more than 25ipm.

EDIT: I may be inaccurate with my 150ipm statement. Based on a bit more research the speed probably will be much lower than this.

WoWWWW!!!!! Thanks for the website Ross. I did some quick pricing and it looks like I can get everything I need for under 7,000$. http://www.cncrouterparts.com/crp4896-4-x-8-cnc-router-kit-p-139.html Right now I'm ordering some more of my HIPS material and sending it out to be cut. Thanks a lot for this info.

[Rodne Gold]

I don't know the exact specs of the blade , but it was one that is specifically for plastics. That link I posted a few posts ago has the specs for a blade specifically for HIPS.
A rule of thumb re router bits is that the max depth of cut in softer stuff = the radius of the bit , however we take real deep cuts in plastic using a 1/2 round D type carbide bit (like an engraving cutter) but with no tapering tip
The secret to cutting plastics with any bit is a HUGE amount of back clearance to aid swarf removal which serves to stop the bit clogging and thus no friction melting the material and , if possible , cooling which has the added benefit of making for really nice and smooth cut edges (you can either use a water system , or soapy water , or better still one of those venturi type coolers)
We cut right through 1/4" plastic type material with a solid carbide 1/8" diameter bit in a single pass..we pay almost nothing for these as we collect broken carbide drill bits from the local PCB manufacturer and use a cutter grinder to make them. Key to taking such deep cuts is to have VERY LITTLE of the shank protruding out the spindle collett , as the longer the bit , the more flex and this gives a bad cut. If you go with a router , get a nice potent spindle , 3-5hp will work well.

[George D Gabert]

If you got a machine with pass thru you would only need a very short machine that was the width of your sheet. you would but your material in and use a bump stop to locate the sheet. Make your cross cut which would be at the edge of your table. When the part cut thru it would drop down into a hopper. The edge of the sheet would be held down by the feed rolleror above sheet guide. This could be automated so the only manual operation would be to load the sheets and clean the hoppers.

[Brad Scoggins]

Hello Everyone,

I'm not trying to hijack a thread here, but I saw some comments about upgrading optics. I have a Gweike on order and was about to start looking at options on lenses. I'm about 4 months into older threads and still going, but I haven't seen much on this. Can someone point me in the right direction? Is Edmond the big player or is there some middle ground?

Thanks to everyone in advance. The friendliness of the folks on this forum is amazing!

Best regards,
Brad

[Dan Hintz]

What are you trying to upgrade?

Edmund's is one of the most expensive places to get optics...

[Brad Scoggins]

Hi Dan,

The focal length of the final lens for starters...

Thanks,
Brad

[Dan Hintz]

Speak to Gweike and order extra lenses from them... it's a lot cheaper to just have them throw it in the package before it ships.

[Brad Scoggins]

Thanks Dan!