agrasyuk Posted March 1, 2013 Posted March 1, 2013 (edited) Good start. What precision setting were you using? How long the engraving job was running? Are you firing laser both ways? Text is straight. Perhaps its the picture or my monitor but It almost looks like the work either shifted during the process or the beam slightly out of focus. Before you do anything take care of fume extraction ASAP. MMA fume while not specifically toxic is not a good thing to breathe at all. Engraving is ok but for cutting I used to set the job running and leave to do CAD work for 15-20 minutes till the underpowered vent cleared the room . now with much better fan it is still not 100% extraction, but at least it clears in under 5 minutes. I'm planing on having extraction system around huge stationary blower fan on garage attic in the new place Edited March 1, 2013 by agrasyuk Anton. My pit build thread . Simple and cheap UFC project
donbinator Posted March 1, 2013 Author Posted March 1, 2013 Good start. What precision setting were you using? How long the engraving job was running? Are you firing laser both ways? Text is straight. Perhaps its the picture or my monitor but It almost looks like the work either shifted during the process or the beam slightly out of focus. Before you do anything take care of fume extraction ASAP. MMA fume while not specifically toxic is not a good thing to breathe at all. Engraving is ok but for cutting I used to set the job running and leave to do CAD work for 15-20 minutes till the underpowered vent cleared the room . now with much better fan it is still not 100% extraction, but at least it clears in under 5 minutes. I'm planing on having extraction system around huge stationary blower fan on garage attic in the new place The runtime for both cutting and engraving was about 3:26 for the top panel. I'm doing the cutting at 100% power (50W) at 20mm/sec and the engraving at 200mm/sec 20% power (I think, I'm not at home right now). I leave the paper on the bottom but obviously not the top as I spray painted it. I might reduce that a little since as Gremlin77 pointed out it's carving into the panel. I have no idea what my "precision settings" are. I'll have to go stare at the settings for a while to figure out the software and what I can change there. What do you mean by "firing the laser both ways"? Yes I usually hit "run" and leave the garage as well. The fumes mostly go outside but I can definitely smell it so obviously some of them are coming back in. Really doesn't smell much more than when i have carpet installed in my house though. I am trying to figure out a way to route the exaust to a dedicated hole in the wall and I'll definitely get a bigger fan.
donbinator Posted March 1, 2013 Author Posted March 1, 2013 In the past I used painted acrylic, two. Now I use a double layered plastic you can buy for laser engraving. It's a white plastic with about 1.6mm in thicknes with a thin top layer of black plastic you laser away to see the white plasic. This gave me the best results and the black top layer is not as sensitive to scratches as paint is. BTW you can buy a lot different color combinations. Look at ebay or a shot for engraving equipment. The one I use is named LASERPLY. Yeah I had seen you or someone post about that stuff. Looks interesting and I may do that. There's a plastics shop right by my work that cuts to size while you wait which I used for the first panel, but it was expensive (3 500x300mm sheets cost about $44 US :(. Convenient though :). What do I use to cut this stuff? I'm using shot acrylic (not extruded) and it seems kind of brittle. I have a small band saw, but haven't tried that yet. They use a table saw at the plastics show but I haven't had a chance to look at what teeth they are using.
agrasyuk Posted March 1, 2013 Posted March 1, 2013 For 3mm and below thickness material I score it with scoring tool against a ruler. After a few phases with the blade it can be broken off clean. For the 6mm material I use reciprocating saw with fine steel blade on slow speed and masking tape. Funny how its the tape that makes it possible, otherwise hot acrylic clogs the fine teeth of the blade Anton. My pit build thread . Simple and cheap UFC project
metalnwood Posted March 1, 2013 Posted March 1, 2013 Donbinator, there is general agreement across the net that you dont want to run the laser at 100% power as it will reduce the life of it a lot more quickly. See what speed to need to run at to cut with 80% to conserve your tube. The only time I have cut higher that 80% was on very thick acrylic and I needed to reduce the speed significantly so I went a little under 90%. Even cutting 5mm/sec is OK, it takes slightly longer but you are not doing lots of them.
donbinator Posted March 1, 2013 Author Posted March 1, 2013 Donbinator, there is general agreement across the net that you dont want to run the laser at 100% power as it will reduce the life of it a lot more quickly. See what speed to need to run at to cut with 80% to conserve your tube. The only time I have cut higher that 80% was on very thick acrylic and I needed to reduce the speed significantly so I went a little under 90%. Even cutting 5mm/sec is OK, it takes slightly longer but you are not doing lots of them. Ah!!! Thanks for that! I'll recalibrate based on 80% then. I should have thought to find out more about that. I fly RC aircraft and you rarely want to charge LiPo batteries at their rated charge rate if you want them to last, should have figured it would be the same kind of deal for the tube and its power supply.
Gremlin77 Posted March 1, 2013 Posted March 1, 2013 I use a jig saw witch an extreme fine blade with lots of teeth for acrylics. For the Laserply you can use simply a cutter knife. I always cut to 600x300 mm for a hole plate that fits in the laser and then move the inital point for each panel I cut from the plate visit my build thread Gremlin's A-10 :thumbup: http://forums.eagle.ru/showthread.php?t=86916
agrasyuk Posted March 1, 2013 Posted March 1, 2013 Yeah, my tube never went above 75% power. For thick stuff i just do several passes. You lucky guys with huge surface areas. On paper I have a 300x200mm but in reality its even less. Not limiting as far as what panels I can make but caused unneeded waste and a lot of micromanagement of leftovers. Will be selling my K40 and going for a bigger one once we move and settle. Anton. My pit build thread . Simple and cheap UFC project
metalnwood Posted March 1, 2013 Posted March 1, 2013 Doh, I wasnt thinking. I was wondering why you guys were not cutting it on your laser! I guess I am spoilt with my 1500x1200mm table :) I have cut acrylics no problem on either a tablesaw or a bandsaw. For the bandsaw I would probably go more TPI than less.
Gremlin77 Posted March 2, 2013 Posted March 2, 2013 1500 x 1200 !!!! no I'm not jealous.........or perhaps a bit......no I AM JEALOUS!!! but I am lucky,'cause for bigger parts I have cnc milling machine with 1500mm x 1000mm from pre-laser-times. But I hate always attending to calculate the loss for the diameter of the milling cutter on the parts. And no real edges. Always this studid radius in every corner visit my build thread Gremlin's A-10 :thumbup: http://forums.eagle.ru/showthread.php?t=86916
donbinator Posted March 2, 2013 Author Posted March 2, 2013 Well I think I figured my "precision" settings out. :). I turned down this, turned up that, and ended up with a near perfect elec panel. I'll take a picture some other time but it turns out that there's a setting for the resolution of the scan, and it was set to 0.1mm. I set it to 0.05mm and it made a pretty significant difference. I'm stoked. You know what though? The smell from the laser cutting seems to be 80% from the actual panel after you remove it. That is, you can have the best fan in the world, but once you remove the panel and wave it around your house bragging to kids and wives who really don't care or even quite grasp what the heck it is you are spending all that time in the garage for, the entire house smells :(. Does washing them help?
Gremlin77 Posted March 2, 2013 Posted March 2, 2013 I do not wash the parts at all after cutting. But I didn't have this effect that the part smells that way. Remember, when you cut something with a laser, you do not realy cut, but you vaporize material. So please check if your pressurized air blown in the focus lens head of your laser is working and turned to max. 'cause if you dont blow your fumes away from the focus lens (and so off the part) you will soon have problems with your laser focus lens because the fumes lay on the lens and your laser can't get through! visit my build thread Gremlin's A-10 :thumbup: http://forums.eagle.ru/showthread.php?t=86916
metalnwood Posted March 2, 2013 Posted March 2, 2013 (edited) 1500 x 1200 !!!! no I'm not jealous.........or perhaps a bit......no I AM JEALOUS!!! but I am lucky,'cause for bigger parts I have cnc milling machine with 1500mm x 1000mm from pre-laser-times. But I hate always attending to calculate the loss for the diameter of the milling cutter on the parts. And no real edges. Always this studid radius in every corner I am also jealous then :) My metalworking mill is manual, I have to turn knobs but I do have a DRO. The table is 1370x255. I can up you on my CNC router though :) 2500x1300 with a 6hp spindle. Before you say it - I saw your tornado frame damn you! :) I now do all my aluminium work on that as it turns things out so well. While I had my morning coffee I poured over a pamphlet sent out my a local machinery supplier with this months specials. It's magic having a coffee thinking about all that stuff you could have..... Just money getting in between us. Yeah, inside corners are a bit of a pain though for cutting out kits like y2kiahs. Back on topic.. Donbinator, the parts will have an odour for a bit but thats not as bad as all the fumes escaping inside from the cutting process. Your laser probably has a setting for the scan gap, not DPI. here is a chart giving approximations http://www.rabbitlaserusa.com/Manuals/Scan_Gap_to_DPI_25.pdf You started with about 250 dpi and with 0.05 you were at 500dpi. I use this for my panel engraving but it takes longer. For other things that dont matter as much I lower the resolution and it speeds things up. MDF can have a really nice smell of some exotic wood used when smoking food :) Edited March 2, 2013 by metalnwood
donbinator Posted March 7, 2013 Author Posted March 7, 2013 I do not wash the parts at all after cutting. But I didn't have this effect that the part smells that way. Remember, when you cut something with a laser, you do not realy cut, but you vaporize material. So please check if your pressurized air blown in the focus lens head of your laser is working and turned to max. 'cause if you dont blow your fumes away from the focus lens (and so off the part) you will soon have problems with your laser focus lens because the fumes lay on the lens and your laser can't get through! Gremlin77, I figured out that the paper on the back of the plastic which I was leaving on was absorbing the smell. As soon as I took it off and wiped off the plastic the smell was almost immediately gone, whereas before that I couldn't keep the piece in the house. Do you cut the plastic with the paper on it? I have been leaving the paper on except for the engraving.
metalnwood Posted March 7, 2013 Posted March 7, 2013 What are you using for a table? Often when you cut on a solid table then the vapours will get trapped under the piece you cut and condense in to a sticky smelly mess. When you take the paper off then it will go with the paper. If you cut with the paper off then it will condense right on the acrylic. I am not sure if this is your issue? What do you lie the acrylic on when you cut? A knife edge table, honeycomb or a solid surface? If my parts are dirty then I clean them with isopropyl alchohol. I always rub my engravings with it because the dust settles around the engravings. I buy it in bulk rather than a small amount from the pharmacy.
Gremlin77 Posted March 7, 2013 Posted March 7, 2013 My plastics have no paper on. They have only a foil on top and bottom side. This I have to wrap off, cause it melts. visit my build thread Gremlin's A-10 :thumbup: http://forums.eagle.ru/showthread.php?t=86916
metalnwood Posted March 7, 2013 Posted March 7, 2013 In my part of the world cast acrylic comes with apaper backing on one side and extruded acrylic is covered both sides. Any chance you are using extruded acrylic? If so you would like cast acrylic a lot more.
Gremlin77 Posted March 8, 2013 Posted March 8, 2013 I use extruded acrylic. What in your oppinion is the advantage of cast acrylic? It's more expensive, this I know. And less brittle. visit my build thread Gremlin's A-10 :thumbup: http://forums.eagle.ru/showthread.php?t=86916
metalnwood Posted March 8, 2013 Posted March 8, 2013 Cast acrylic will cut a lot nicer on the laser. The extruded acrylic melts more that cuts. If you cut something like a small gear wheel in both you would see the difference fairly clearly. Next time you pick some up see if you can get an offcut to try out. Where I get mine they give away small offcuts unless I want half a dozen of them then they usually get a few bucks for it.
donbinator Posted March 8, 2013 Author Posted March 8, 2013 Mine is all cast. Didn't know there was a difference until the guy at the plastic shop talked to me about it. He also said that cast cuts a lot nicer with laser cutters. Almost all colored acrylic is cast, at least at my provider. Mine is covered on both sides though with paper. I tried a cut without paper on either side. it worked fine but left a liquid (which never hardened) laying around. I'm afraid to ask what it is...
Deadman Posted March 8, 2013 Posted March 8, 2013 ectoplasm slime :thumbup: https://forum.dcs.world/topic/133818-deadmans-cockpit-base-plans/#comment-133824 CNCs and Laser engravers are great but they can't do squat with out a precise set of plans.
metalnwood Posted March 9, 2013 Posted March 9, 2013 yeah sorry, there is paper on both sides on cast. Was having a brain fade because I take off one side first and am so used to seeing it that way.
donbinator Posted March 12, 2013 Author Posted March 12, 2013 ectoplasm slime :thumbup: LOL!!!! Perfect description. Smells like it too.
donbinator Posted March 15, 2013 Author Posted March 15, 2013 Hey I'm having a rough time figuring out how I want to implement the front panel. I plan on using a 28" Hanns G monitor I scored off of ebay, but I'm not sure how to implement the front panel. I was planning on using Helios, and have everything all mapped out in a profile, but I don't need to use any of the input capabilities of Helios. Do I really need Helios? It won't let me move the MFD's off far enough to the sides so that the buttons are off screen (maximiming the monitor space, since I'm using the TM MFD's). Also, how do I get the dimensions for the cutouts of the front panel? I figure it's OK to build up with 3/4" MDF for bevels with switches in front of whatever I end up using as the front panel. What are you all out there in A-10C land doing for yours? Ideas?
donbinator Posted March 15, 2013 Author Posted March 15, 2013 Hey I'm having a rough time figuring out how I want to implement the front panel. I plan on using a 28" Hanns G monitor I scored off of ebay, but I'm not sure how to implement the front panel. I was planning on using Helios, and have everything all mapped out in a profile, but I don't need to use any of the input capabilities of Helios. Do I really need Helios? It won't let me move the MFD's off far enough to the sides so that the buttons are off screen (maximiming the monitor space, since I'm using the TM MFD's). Also, how do I get the dimensions for the cutouts of the front panel? I figure it's OK to build up with 3/4" MDF for bevels with switches in front of whatever I end up using as the front panel. What are you all out there in A-10C land doing for yours? Ideas? To be clearer, the monitor is for the instruments behind whatever I end up coming up with for the front panel....
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