Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: rabphxaz on October 31, 2008, 01:11:55 PM

Title: general newbie questions
Post by: rabphxaz on October 31, 2008, 01:11:55 PM
Hello all,
I have just finished the physical construction of a 24" x 36" router table and am now getting to the software part. I am a cabinet maker by trade, and what I want to do with my cnc machine is the make shallow area routes of flat cabinet doors so that I can inlay veneers into the routed areas. I will make the inlays myself on a bandsaw, and they will be about 1/16th inch thick. The routed areas will be freeform, that is, I want to hand draw, for example, a bird in flight, transfer the drawing to the veneer, cut the veneer into the bird shape, use the cut veneer to make a line drawing of the outline of the veneer bird, take a picture of the line drawing with a digital camera, download the pic into my pc, use a scan-to-CAD system to change the line drawing from raster to vector, have it expressed as a DXF file...and this is as far as I go. (Do I get extra credit for run-on sentences?). I don't know what my next step should be, but I think I need to buy both a CAM software system such as MasterCam to translate the DXF file into Gcode, and a motor controller such as Mach3. Or maybe one of those systems will act as the scan-to-CADer? Do I need to combine the pc requirements (ram, cpu size, etc.) for both the CAM system and the motor control system to have a pc with the capabilities to run both? I have a whole bunch of dumb questions like that, but you get the idea -- I need advice, and would appreciate any help you can offer.
Thanx, bob
Title: Re: general newbie questions
Post by: RICH on October 31, 2008, 05:19:44 PM
You can do a search for raster to vector file software and will fiind some posts. My experience is that raster to vector software "sucks" and i don't care who makes it and how much you spend. Should you find something that truely works
please post as I would be interested along with a lot of companies.

You can take your picture or scan and draw over it CAD. Place know accurate markings on it which are visual in the picture.
Import to CAD, scale it to size, draw over the figure, export as a DXF file. You will need a CAM program to generate the code for the profile / whatever from the dxf file. You can try LAZYCAM ( its beta ) which may or may not be for you, or purchase some other program. You should try a number of programs to see what satisfies yourself in a price range that suites you wallet.

Recommended pc for Mach should be adequate for most software. Windows XP 1 GHZ W/ 1 TO 2 GHZ ram are about norm
today.  Avoid on-board graphics if you can. If the pc turns out to be a problem the Super Stepper which uses the USB should be considered ( consider one right from the start).

You'll need controll software , of course MACH since it's the best in town, and a contoller composed of the power supply/ motor drives/ cables.
Hopes this helps and just my opinions,
Title: Re: general newbie questions
Post by: Glenn on October 31, 2008, 06:15:09 PM
Rich is Right! :)
  If you would like to try the tracing  over the top of your imported picture for free,
go to solid edge 2 d free. If you trace with your mouse over the photo (helps to magnify
your picture alot), solid edge will create a dxf file that Lazycam will resize and relayer if need be,then, try mach3 to see it cut out your hand drawn image! The free version does  have a limit on the g- code, but you will get the idea.

  I use this system, and it works for what I need

      Good luck, Glenn

Title: Re: general newbie questions
Post by: Sam on October 31, 2008, 06:16:42 PM
raster to vector software "sucks" and i don't care who makes it and how much you spend
I agree with Rich.

I will make the inlays myself on a bandsaw
Why are you choosing to do this by hand? If your reasoning is "because the veneer is thin"....Thin parts can be cut by sandwiching between two pieces of thicker material. "spoil boards" or "sacrificial boards" are a common reference for them.

If it were me, I would choose to do it in this manner.

Draw the pattern in cad (or cam), OR....
Freehand the pattern, scan your pattern to the computer using a scanner, then trace over the scanned image in cad.
Import the cad drawing into your cam program.

Basically what you are doing is making an outline to use as a tool path for the veneer AND the pocket in the door. Using the same outline for both parts ensures a much better fit.
I would stay away from taking a picture of the part or drawing, and then manipulating the picture to create a tool path. A camera will NOT take a truly flat 2D picture, and therefore can cause all sorts of grief for you. Especially since your needing a reasonably tight fitment.
If your putting this pattern on more than one door, you could also consider stacking the veneers together between the spoil boards and cutting several at the same time.

If all your doing is making simple pockets and outlines, there should be no reason to sell a kidney and buy Mastercam or some other expensive software. Some cam programs will allow you some cad ability, therefore eliminating the need for the cad software, and importing/exporting files between the two.

Good luck with your endeavor.

Title: Re: general newbie questions
Post by: rabphxaz on October 31, 2008, 07:27:13 PM
Wow, this Forum thing really works! Thank you very much for the feedback.
Re: the point Rich makes about the scan to CAD software sucking, I have been in touch with a firm in Britain called, appropriately, Scan2CAD at the website. I sent them a digital picture of a line drawing I had made and photographed and they sent back a file, which, of course, I can't open because I haven't installed a CAD/CAM system yet. However, they said their software will do this no problem. They also said that the file they sent back contained Bezier curves, and since some software can't handle Beziers (I guess because they're algorithymic), they asked if I would like them to do it using arcs, which, they say, is also no problem. I spoke with them on the phone and they sound very conscientious and knowledgeable, and I have the feeling that they know a thing or two. If anyone would like to see the file the sent, I will forward it to you-- maybe you can tell me if it looks good or not.
As to the suggestion "You can take your picture or scan and draw over it CAD", I'm not sure what that means. Does it mean that I download a scanned line drawing into a CAD program, magnify it, and then use a pointer to convert it to a CAD drawing. kind of like what Glenn was saying?
Also, maybe I should explain something about my design method, because it may impact on what Sam said and scanning in general: I'm treating cabinet doors as a group, that is, all the faces of a group of upper cabinets may contain, for instance, a flock of birds, or a vine with flowers that travels across all of the doors. The base cabinets might be a garden scene or desert landscape. I like to work in full size, so what I will do is cut large white poster cardboard the same size as all the doors and tack them to a wall in order, and then place my cut veneer pieces on them in the pattern I want. It is easy to then trace the veneer pieces with a black pen, and the result is that each representative poster door has a line drawing that can be photographed. I think if I set up my camera from across the room, and include a scale somewhere on each poster, I will get an accurate digital file that can be scanned to CAD. I think I want to do it this way because the door sizes are all different, and larger than what you can run through a scanner.
As far as cutting the veneer, I have a scroll saw that does a good job. I understand that I can use sacrificial boards to get good edges, and I will do that in the scroll saw, but I don't want to cut the veneer with the CNC because it doesn't allow me see the veneer on the door-sized posters, and I need to see that. I make a lot of changes at that stage.
I'm going to try what Glenn suggested and go to solid edge 2d, but please keep it coming. This is all VERY helpful.
Thanks again, Bob
Title: Re: general newbie questions
Post by: ger21 on October 31, 2008, 08:39:00 PM
I don't think this will be very easy to do, the way you want to do it.

As was mentioned, raster to vector programs will probably not give you usable results. I've periodically looked at different ones over the last 10 years, and haven't seen one that I'd use. Of course anyone selling a raster to vector program will tell you how great their's is. They'll all convert your image to a vector file, and even the free ones will do it pretty well. The key, though, is that these conversions aren't very good when it comes to using them for cutting parts. When you zoom in closely to look at them, they are composed of LOTS of short segments, very jagged, and going in all different directions. A simple curve that could be drawn in a CAD program with a single arc, might consist of 100 segments in a raster to vector conversion. This is important, because when you create g-code form your .dxf file, the tool will follow the vectors exactly as they appear in the .dxf.

As for your other questions.

MasterCAM is about $10K, and is far more than you'll ever need.  A very good package for woodworkers is Vectric's V-Carve Pro. It's a very capable CAM program, does very good raster to vector conversion, V carved lettering and also has some basic drawing and vector editing. Support is second to none as well.

You'll also need a control program like mach3, which is what actually runs the machine.

Computer specs are not cumulative, however, if you want to use one PC for both CAD/CAM and machine control, be advised that while the machine is running, you really shouldn't be using the PC for anything else. Separate PC's is a good idea.

Tracing in CAD. What that means, is load the image into the CAD program, and manually draw right over it in your CAD program. The CAD program will have commands for lines, arcs, curves, and other entities. You use these to draw your shape, using the image as a guide.

I'd recommend that you start downloading demo and trial software and try to do what you want, and see if it's feasible. Feel free to ask a lot of questions along the way, because the learning curve may be steep.

I don't think you'll be able to get clean, tight joints on your inlays with your method. Ideally, you'd draw the whole thing in a CAD or design program and skip the raster to vector step. But that will require you to get good at a CAD or design program. :) In the meantime, I think you'll get better results by hand tracing in CAD, or hand tracing over your raster to vector conversion (to clean it up). Then, I'd print out scale drawings to use as templates to cut your veneer to, so that you can get as close a fit as possible.
Title: Re: general newbie questions
Post by: Sam on October 31, 2008, 11:40:51 PM
I don't think this will be very easy to do, the way you want to do it
Hehe.... I don't think it will be easy ANY way you do it  ;D
However you decide to do it, be prepared for a very steep learning curve.
travels across all of the doors
Ahhh... A mural, or landscape. Now you have to share pictures of your projects!  :) We would love to see some!

the door sizes are all different, and larger than what you can run through a scanner
The size of the final product is usually of no concern with respect to the size of the drawn pattern. You can scale the drawing to any desirable size. You could draw an eagle the size of a quarter dollar, and cut it on the machine as big as the machine capacity. If you feel that you make your designs best at full size so you can have a real life visual reference, well then I totally understand that. You could draw the whole cabinet system in 3D, but I understand that a computer model is not the same as a physical model. It is a barrier that we all have to overcome in some form or fashion to really tap into the designs in our head.
Out of curiosity, did you build the machine for the intent on inlay work, or was your primary concern with making repeatable parts in quantity, such as frames, dovetails, etc...?
A website that might be of interest to you is ecabinets. if you've not already found it.
Title: Re: general newbie questions
Post by: RICH on November 01, 2008, 07:46:35 AM
What you want to do requires some manipulation / time / work and some accurate drafting.
I will just give some concept here then you can play around with it.
If you use a camera, the better the resolution, the more accurate will be the CAD overdrawing
on the image. You will be drawing over pixels probably. I have done this with microscope pictures and dims can match to
one or two ten thou's. Accuracy varies as distance increases but still can be quite good. Of course the optics come into play.
In general, with camera at center point and focus perpendicular to plane then a=a, b=b and any distance about center
line both in height and width can be drawn, measured or even calculated anyware along the sighting of the plane.
Of course knowing where the camera is relative to the plane is required ( especially if not on center of the plane ). this poor man's laser photogrametry. Attached picture should help understanding.
Have fun and lol,
Title: Re: general newbie questions
Post by: rabphxaz on November 01, 2008, 10:35:34 PM
OK, I have spent the day doing CAD tutorials and thinking about what everyone has said, and here are my thoughts now:
1.) As per Glenn's suggestion, I went to solid edge 2, and I don't think that will work for me. The site, I think, is aimed at CNC professionals, and they assume that you have a lot of  CNC-specific knowledge and nomenclature that I don't have.
2.) As per ger21's advice, I went to Vectric's website, and I think they may have what I need. From reading their information, I believe that their software will allow me to trace over a line drawing the get it into a DFX file. I posted a question similar to my initial one here on their forum, and will see what they have to say. Also, ger21, I think your idea of printing out scale drawings to use as templates for the veneer is great -- it started me thinking that I could use colored paper the make the designs, rather than veneer, I can cut paper with scissors, which makes changes easy, and there's no waste of veneer. I can then use Sam's idea about using the cnc  to cut both the inlay area and the veneer.
3.) Sam, I will be happy to share pics with everyone, and as to your question of my original intent, I built the machine specifically for doing the inlays. I'm kind of a one man show, not a big production cabinet maker, and I don't think I would use a cnc to drill hinge holes or cut doors.
4.) Rich, I understand what you are trying to convey re: how photographing will distort the scale of a drawing. My plan was to zoom in on each door panel from far away, thereby reducing the distortion effect. Do you think that will work?
5.) MasterCam is $10K???? Jesus.
6.) I can't tell you guys how much I appreciate all the effort and thought you've put into this, but I want you to know that it has been very helpful. Please send anything else that occurs to you, and I will let you know what I get back from Vectrics.
Thanks again, Bob
Title: Re: general newbie questions
Post by: rabphxaz on November 03, 2008, 10:04:53 AM
Here's a question: In the Features section for Mach3, it says that it "allows direct import of DXF, BMP, JPG, and HPGL files through LazyCam."  Does this mean what I think it says, that I can load a Jpeg or BMP into LazyCam, and either it or Mach3 will convert it to something that they can generate Gcode from? This would eliminate the need to trace over the JPEG with a CAD program in order to do the conversion. Does anybody know if this is true?
Thanks, Bob
Title: Re: general newbie questions
Post by: ger21 on November 03, 2008, 11:02:46 AM
  Does this mean what I think it says, that I can load a Jpeg or BMP into LazyCam, and either it or Mach3 will convert it to something that they can generate Gcode from?

No, not what you think. LazyCAM will create g-code from the image, but the g-code will be for a 3D carving of the image, not a trace of it.
Title: Re: general newbie questions
Post by: rabphxaz on November 03, 2008, 08:59:13 PM
OK, then how about this: if a CAD image contains Bezier curves, can LazyCam handle it, or does it work with arcs only?
Title: Re: general newbie questions
Post by: ger21 on November 03, 2008, 09:35:24 PM
I don't think so. But at some point, the bezier curves (or splines) need to be converted to arcs or line segments, because there are no g-codes for bezier curves.