RE: Need a reason to keep my Laser Cutter
 

Mooney Driver- Welcome to the thread. I'm not sure how to import a jpeg and then scale it to the size you want with the software you are using. It is however very easy to do with Delta Cad. I know there is a short tutorial on accomplishing this with Delta Cad on Youtube, just search for Delta Cad. I'm sure there is also a tutorial for your software on youtube.

RE: Need a reason to keep my Laser Cutter
 

After I have drawn all of my parts I copy all the parts of a given size of balsa to another layer, but you could probably more easily do this by copying to another area of the drawing space. In any event I then draw the print area and the balsa sheets in a color that does not cut and then arrange the parts as I want them on these sheets. They are then ready to send to the laser.

Here is a jpeg of the parts layout for a plane I copied from plans and cut with the laser. I'm building it now.

If it looks like some of the lines are incomplete it is because of the scale. When I zoom in everything shows up fine. The font used is a single line font converted to lines and arcs so it vector marks instead of raster marks.

RE: Need a reason to keep my Laser Cutter
 

One error you may notice in the above drawing is that my gaps in some of the lines that I use to keep the parts attached to the sheet, are placed without regard to the wood grain. The gaps work best if they do not cut across the grain, you want the grain to flow through the gap.

RE: Need a reason to keep my Laser Cutter
 

049 Flyer, where were you 2 years ago when I bought my laser and TurboCad? [:@] Great thread explaining most things I had to learn thru hard knocks and others on this site.

Mooney Driver, here is how I do it:

Importing Images Into TurboCad

1. Copy PDF plan onto 8 ½ X 11 sheet of paper.

2. Scan the plan you just made and save it as a bitmap. (They just seem to do better.)

3. I have a trace drawing template (has fonts, line colors, styles etc) and I import the drawing into that by going to “Insert”, “Picture”, “From File”.

4. The put cursor on the 0,0 axis.

5. Click and hold left button and move the cursor in the x axis direction to the desired width. You must keep it below 0 on the y axis otherwise the drawing will be upside down. If there is a scale on the drawing this helps very much, if not, you must use a dimension that is known. The longer the better. This is the only tricky part and as stated, is trial and error. I usually write down all the ones that I tried so as not to repeat them. Here is an example: There is a scale on the page says 12 inches. You import the drawing and on the x axis you release the right button on the mouse and it is at 42 inches (the wing size will give you a general starting point). Once you let go of the mouse button, the drawing will appear. Now go to the scale and use TurboCad to measure. If it isn’t 12 inches (say it’s 8), you need to import another one. What I do now is do a proportion. 42 is to 8 as 12 is to X and solve for X. That will be real close to where you need to drag the cursor to on the x axis. In this case , X will be 63. So, when you import the next drawing, put the cursor on 0,0 and hold the right button down and move the cursor over to the 63 inch on X axis and release button. Remember to stay below 0 on the y axis. (You don’t need to worry about the y axis, guess it is proportionate to the x axis??????) Measure scale again to see if it is accurate. May need to tweak and tune to get exactly right. (I have it down to usually not more than 4 attempts. In the beginning it was 10 – 15, but that was before I started using proportions.)

6. Save drawing how you wish. I have on my template as the color black being bitmap. I then do all my tracing in yellow. You can turn off the black and the only thing left will be what you traced. I save all my drawing for a particular plane in the same file. If you erase the saved file that was scanned, you will lose your imported drawing in TurboCad. I discovered this the hard way.  Also, if you copy an imported drawing onto a thumb drive and install it on another computer, the imported drawing will not appear. You can go to “tools”, “raster image”, “image manager” and then embed and apply, this is suppose to prevent from losing imported image. Not sure since I now save the bitmap image in the same file.

John

RE: Need a reason to keep my Laser Cutter
 

Welcome Rubbernecker!

Please feel free to add any pearls of laser cutting or CAD drawing wisdom you have so that all of us can learn how everything works together.

By the way my laser power is 30 watts and i feel it is enough to cut anything I need to cut although sometimes I have to slow it down a bit. I have cut plywood up to 1/4 inch and balsa up to 1/4 inch. I think I can cut thicker balsa but never had the desire to. I'm pretty sure that 1/4 inch plywood is about it though.

Tried cutting formica the other night to make foam wing cutting templates. Cuts slow but very nice and smooth. A little sanding and I have a foam wing template many time more accurate than if I cut it myself on the jig saw.

RE: Need a reason to keep my Laser Cutter
 

Are you cutting aircraft ply or lite ply? I have a 40 watt laser and anything over 1/16 ply on the aircraft ply gets very burnt and takes forever. It cuts lite ply very good. Same deal with balsa over about 3/16. I have cut some profile ukies and found out it's just best to laminate. 1/8 lexan cuts great (made a few tools) but it stinks to high heaven. My laser is only 9 X 14.5. Is a perfect size for half A much like yours. Just have to piece things together like Goldberg did. Not a big deal. Being able to make your own far outweighs the inconvenience. Plus, once you put the parts in a cut file, all of them made from that point will be the same.

I drove thru Tyler Texas (destination was Athens) to pick up a Powered Parachute 6 years ago. Poor mans airplane! Left Friday morning and was back in my driveway Sunday morning 9:00 am. A man chasing a deam is a dangerous thing (getting in his way that is). :D

Take care,

John

RE: Need a reason to keep my Laser Cutter
 

Rubbernecker

It's all about the glue!

It's seems obvious that the most important factor of a laser's ability to cut stuff is it's power, expressed in watts. But there are other factors of equal importance.

The laser operator can adjust the speed that the laser travels over the work, the power in an almost infinite number of steps and the number of laser pulses per inch of travel. Laser manufacturers publish rough guides to get operators started in finding the best combination for their machine and materials they will use most often. However trial and error is the only way to fine tune the process.

But the most important factor especially for lower powered systems is the material to be cut and it's thickness. The laser can cut a variety of materials like wood, acrylic, rubber stamps, and leather. It can etch all of the above plus painted brass, and anodized aluminum.

One particular material that really baffled me for a week or two was plywood. Not lite ply so much, (it was easy to cut), but the stuff you make firewalls with. After setting my machine up I started cutting balsa wood and through trial and error soon found the settings that resulted in nice cuts in the thicknesses I use most often. I then grabbed some plywood and immediately hit a brick wall.

After days spent ruining sheet upon sheet of plywood I was convinced I had purchased a machine without the power I needed to cut an essential modeling material. I could barely cut 1/16 inch plywood and only with quite a bit of charring. I was quite upset. I normally default to the cheaper less feature laden device when deciding on what to buy. It seemed that this time my frugality bit me in the butt. I wondered if I should have bought a more powerful machine.

One particularly frustrating afternoon spent burning plywood, I had the idea to look in a laser cut kit I had laying around. I immediately noticed that the plywood they used was different than the plywood I was using. I took a small piece of the plywood from the kit, put it into my laser cutter and tried cutting it. Eureka! Nice cut minimal charring. But what was the difference and where could I find this special plywood.

I spent several days researching all the varieties of plywood and how it is manufactured. Soon I was a plywood expert!

The bottom line? I discovered that Laser cutters have a very hard time cutting phenolic materials and it just happens that waterproof or water resistant plywood is glued together with phenolic glue. Seems impossible that just a slight amount of glue between each layer of plywood could make such a difference but multiple tests proved out my theory. It does make a huge difference, especially on my 30 watt laser. Now using the right plywood I can cut up to 1/4 inch ply but rarely do, I cut 2 pieces of 1/8 and laminate them if I need 1/4 inch.

The good news is it's easy to tell if the plywood is assembled with phenolic glue. Phenolic glue is visible as a very thin black or dark brown line running between the layers of wood that make up the ply.

I took a picture so you can see what I'm talking about.

Both pieces are 1/4 inch ply and the piece on the left cuts fine but the piece on the right doesn't cut at all!!

What you need to find is INTERIOR GRADE plywood, commonly found at places catering to cabinet makers. It seems the phenolic glue gives off fumes as it ages and is not desirable for use inside dwellings. Ask for interior grade birch ply because birch is the strongest, at least that is what I've been told.

RE: Need a reason to keep my Laser Cutter
 

Very good! So where did you wind up finding the plywood, a cabnet shop?

John

RE: Need a reason to keep my Laser Cutter
 

There is a place in Dallas called Wood World that caters to wood workers and cabinet makers. They have all sorts of hardwood, most I've never heard of from every corner of the earth. They also have many different kinds of plywood including interior grade birch.

Tower Hobbies sells the Revell brand of plywood which works great in the laser but is VERY expensive. You would be much better off to visit a cabinet shop and ask them where to buy what you need. Maybe you can score some scraps for FREE!

Another source would be Wicks Aircraft Supply or Aircraft Spruce and Specialty but it would be difficult to find out over the phone what type of glue is used in the wood. If the plywood is advertised as being waterproof or water resistant then it FOR SURE uses phenolic glue.

Another interesting tidbit. I have been experimenting with plastics and have found one that cuts nicely in the laser and CA STICKS TO IT better than balsa or ply. It seems like it might be a good substitute for plywood; stronger, cuts better and glues STRONG! Stick it with CA and you can't pull it apart before it breaks. CA works better than epoxy on this stuff!

The plastic is similar to what 2 liter soda bottles are made from but lots thicker. I even tried making landing gear with it by heating with a heat gun and bending it, worked pretty good. Not as brittle as Lexan.

A fellow modeler turned me on to it by giving me a bit to try. Cool stuff. I'm going to try it instead of plywood on my next Control Line plane!

RE: Need a reason to keep my Laser Cutter
 

Chiming in here

I have 20 year professional experience with AutoCAD. I am now in the process of trying to get really good at Solidworks. I started this thread a couple of years ago http://www.rcuniverse.com/forum/m_92..._1/key_/tm.htm The lase cutter I found locally had never done an R/C kit before, but in conversations he to;d me he had been contacted by some with PDF, or JPG magazine plans. He had to pass on those because they really are not Laser Ready. He did mine, and was happy to do so because I had done the plans in CAD, and they were totally laser ready.

The advantage of drawing the plan in CAD is accuracy. Digitizing a hand drawn plan, even as good as one drawn by M.Kato is not something he had the knowledge to do. The parts fit will be as close to perfect as you can get, if every thing is done in CAD.

I have a copy of AutoCAD, and would be willing to digitize a set of plans. The cost would be in the hundreds, however. I haven't worked for $3/hr since 1974. (washing dishes at Denny's)

RE: Need a reason to keep my Laser Cutter
 

HI, Will a laser cut 1/6" micarta?

Thanks

Don

RE: Need a reason to keep my Laser Cutter
 

I'm not sure what micarta is. Perhaps someone else will offer an opinion?

As to digitizing plans; yes it does take alot of time to re- create a plan sheet in CAD. I paid someone to do just that for a small .15 glow powered plane I was considering kitting. It cost me a little over $500.00. Very nice job, but very time consumming and therefore expensive.

HOWEVER; you do not need to digitize plans unless you wish to publish or kit a particular model. If you just want the parts laser cut so you can build from the existing plans then you only have to digitize the parts to be cut. MUCH less time involved and much less expense. You can easily do this yourself with simple CAD programs like Delta Cad.

RE: Need a reason to keep my Laser Cutter
 

When you say digitalization of a plan, there are actually 2 ways to do it.
The most accurate way is to draw in cad using the dimensions on the plan,
This way everything will fit. This can take up to 200 hours of work based on complexity of the design.
2nd way is to trace as detailed in this post. This is not accurate but will get you there

RE: Need a reason to keep my Laser Cutter
 

Rubernecker

There is a much easier way to properly scale your bitmap in Turbocad. Inset the file, measure, and find the scale factor as you have been doing. then take that number and enter it into "scale X " box down on the command line. Make sure "Keep aspect ratio" is on. Hit enter and your inserted bitmap will scale up to the proper size.

RE: Need a reason to keep my Laser Cutter
 

I love to scratch build from plans and have been building this way for many years. I used to assume that whenever the parts I cut out from plans didn't quite fit right, it was because I was sloppy or measured incorrectly. Since dabbling in CAD I've discovered that the problem is in the plans. Most plans have many errors which can only be found with careful examination or CAD drawing.

If you want the parts to fit exactly then you will have to spend many hours re-drawing the plans. However you can still get acceptable results by just spending a bit of time checking the plans with a ruler. Then CAD drawing the parts you want laser cut.

RE: Need a reason to keep my Laser Cutter
 

rc extra.... How is the user interface on TurboCad? Is it fairly intuitive or do you need training like you do with SolidWorks? I see
TurboCad has a version for MAC so might go down that road.

RE: Need a reason to keep my Laser Cutter
 

To scale the bitmap in Delta Cad is even easier. Here is a video link: http://youtu.be/6NH4mOUHVik

RE: Need a reason to keep my Laser Cutter
 

Micarta is a phenolic resin often known as bakelite.

RE: Need a reason to keep my Laser Cutter
 

Based on my experience with phenolic glue used in waterproof plywood, I would say that micarta would be difficult to cut. Probably could be done but would take a more powerful laser than what is commonly used to cut wood. The only way to know for sure is to give it a try. If you have a piece laying around I'll be happy to throw it in the laser and see what happens.

RE: Need a reason to keep my Laser Cutter
 

Thailazer

I find turbocad to be fairly intuitive, at least in 2D. There is a bit steeper of a learning curve for 3D, and the photo-realistic rendering which it is capable of is an art all its own. There is an excellent on-line forum for help from other users and some relatively inexpensive tutorials from third party vendors that are very good.

RE: Need a reason to keep my Laser Cutter
 

Alright, walk me thru it, I'm game for knowledge! :D You lost me at "scale factor". I know how to take a full size drawing and scale it up or down but not sure about a drawing that I don't have the size of.

John

RE: Need a reason to keep my Laser Cutter
 

Thanks for that. I guess there still isn't a 3D solution for simple objects for the common hobbyist. I used Home Design Studio last year to design our house and the 3D rendering was great. Best thing though was that the software was so easy to use you basically sat down and started to design. Really impressive to make 2D changes on one display and immediately see the changes on a second display showing a view from a walk through or from a helicopter view. But that is customized for houses only. For stuff like models, TurboCad is probably the easiest one to learn though from what I have seen if you want 3D.

RE: Need a reason to keep my Laser Cutter
 

Alright, walk me thru it, I'm game for knowledge! :D You lost me at ''scale factor''. I know how to take a full size drawing and scale it up or down but not sure about a drawing that I don't have the size of.


Scale factor - If you measure your object as 6 inches and you know it should be twelve then you need to scale it up by a factor of two.

Put that factor into the "scale x" and "scale y" boxes, (or just one of them as long as "Keep aspect ratio" is selected) hit enter and your object will scale up or down by that amount.

RE: Need a reason to keep my Laser Cutter
 

I am amazed by the amount of information flying around in this thread. Thank you to one and all!