[The Wizard]

Hi Folks,

I joined this forum about a week ago and have been avidly going through *all* the information on here......WOW what a wealth of knowledge!

I am about to start building my first home CNC router/engraver and while waiting for parts to arrive I have been playing with LOTS of software packages to see what works best for my needs. I will primarily be using the machine to route/drill circuit boards but would like to use it for engraving and wood carving too.

I think I have found software I can use for the circuit boards and to control the steppers but I am having trouble finding suitable software for the engraving projects I have in mind. I have downloaded the trial versions of both 'DeskART' and 'MeshCAM' but don't seem to be having much luck when it comes to generating the G code to make the parts.

I have a project in mind that would require reverse engraving on clear plexiglas but for the life of me I cannot seem to get a decent G code out of anything. Either the software wants to produce a 'relief carving' (great if I was machining it out of wood but no good for the job in question) or it generates a 'flat plane' G code that does not cut the required pockets/shapes.

I was wondering if anyone on here is reverse engraving/carving plexiglas and if so what steps/software are you using to get your G codes. I have numerous software packages available to me to generate dxf, bmp, gif, wmf files etc. so that is not a problem but I don't seem able to find a way of just engraving the 'pockets' I require. Some of the CAM software also wants to machine the entire top surface too which is obviously not what I need on plexiglas as it would destroy the 'see through' properties I require.

Any suggestions/help would be greatly appreciated. BTW cost of software is a big issue to me as I am now medically disabled and on a very fixed budget so cheap is good! A good friend is actually paying for 95% of the building costs of the machine on the condition I make his parts for him (LOL). I guess I should also say that way back in the early 80's I obtained qualifications as a CNC programmer (all hand coded in those days) but never worked in that field so I am familiar with G codes and CNC machines in general but modern CAM software is something new to me.

Thanks for any help,

Larry Green

[HuFlungDung]

Hi Larry,

You might want to review OneCNCXR Mill Express.
http://www.onecnc.net/products/products_index.htm

This should permit you to machine either simple stick fonts, or raised relief fonts. Other wireframe shape machining will also then be possible for you.

In the past, I used a very simple to use, but dedicated engraving program, called MillWrite, developed by Endpoint software. I haven't kept up with the progress of this software any longer, but I think it has evolved into more than engraving. It might allow more artistic licence when creating artwork for machining, too.

[ger21]

http://www.sheetcam.com

Free right now during beta, and should do what you want.

[ynneb]

Hey Gerry, I notice you always recommend sheetcam. When I go to the site all I see is the download section. There is no other information. Who is sheetcam made by? Is there an instruction pdf I can see regarding sheetcam?

[The Wizard]

Thanks for your help and suggestions guys. I downloaded SheetCam and had a working G-Code file of what I need in about an hour (including working through the tutorials!) The software is very intuitive and the tutorials well written, although you can tell it's a beta version as some of the screen shots do not exactly match the actual screens (I am a former technical writer/illustrator and can't help noticing these things )

Now I need to build the machine and finally decide on which one of half a dozen demo controller packages I am going to use to actually run it. Then I can start making chips/dust :banana: .

Larry Green

[ger21]

Benny, you'll be glad to hear that there is a Yahoo group for SheetCAM.
It's being written by the same guy who wrote the Keygrabber utility for Mach2. When you download it there are tutorials included. I played with it a little a while back, it worked pretty good. He's added a lot of features since I last looked at it. Anyone who needs a 2.5D CAM package should really take a look at it. He's filling the void of low cost 2.5D CAM.

[imserv]

I think I have found software I can use for the circuit boards and to control the steppers but I am having trouble finding suitable software for the engraving projects I have in mind.

Larry, DeskCNC will provide both Cam programming and CNC machine control using a Windows 98 or later computer.

It includes Gerber and Excellon to G-code, DXF for contours, pocketing and drilling, engraving of tru-type text, and image processing with editing, tracing around colors, and depth carving for 3D, and 3D .stl surface machining.

It's all in one package, with inexpensive stepper and servo drivers available for smaller machines.

http://www.imsrv.com/deskcnc

Fred Smith - IMService

[The Wizard]

Thanks for the info Fred.

I downloaded the demo (I already had the demos of DesKam and DeskArt) but I don't think my computer of choice for this project will be able to drive it. I plan on doing the design/conversion work on this one and then transferring the G code file to another computer to run the machine.

I was recently given three old laptops (none working) and I am hoping to get at least one back on its feet and use that as a dedicated unit with the CNC router/engraver/mill. One is a 486 B/W with an intermittent screen problem, one is a P1 (colour) which apparently does run but needs a HD and adapter tray (none installed at the moment) and the third is only good for parts as it is missing the HD, processor chip, CD drive and power supply.

This is CNC on a budget...lol....I haven't had to resort to dumpster diving yet but if I see anything I can use it will come home

Larry

[imserv]

Shoot for at least a P200 and Windows 98 for a machine controller with DeskCNC.

Anything slower/older and Windows 98 probably won't run or there may be wierd things with drivers, displays, ports, etc. especially with laptops.

The 3D surface calculations are fairly math intensive. Plan on a faster computer if you want to scan surfaces and create 3D files and/or toolpaths to re-machine them. Same with the image processing portions of DeskCNC.

I currently do a lot of my testing on an Athlon 900. All the functions work fairly fast at that speed. However the hard drive is 30 times larger and at least 5 times faster than a P200, and it has 8 times the system RAM.


Fred Smith - IMService

[The Wizard]

Hi Fred,

Shoot for at least a P200 and Windows 98 for a machine controller with DeskCNC.

Anything slower/older and Windows 98 probably won't run or there may be wierd things with drivers, displays, ports, etc. especially with laptops.

The 3D surface calculations are fairly math intensive. Plan on a faster computer if you want to scan surfaces and create 3D files and/or toolpaths to re-machine them. Same with the image processing portions of DeskCNC.

I currently do a lot of my testing on an Athlon 900. All the functions work fairly fast at that speed. However the hard drive is 30 times larger and at least 5 times faster than a P200, and it has 8 times the system RAM.

My main computer is also an Athalon 900 and that is the one I will be using to design parts, generate toolpaths and G code etc. Once I have the checked and verified G code file I hope to transfer that to the dedicated computer I will use for the CNC machine. It is physically impossible for me to use this one as it is located in a different part of the house and tied into a network.

I had hoped to use a laptop as I have space constraints to deal with and have several control software demos that will run on slower computers (in DOS if necessary).

Larry

[foamcutter]

Larry,
A while back I did some reverse engraving for some plaques in clear acrylic. This is how I did it actually two ways. #1 generated the words to be engraved in corel draw and reversed them and printed them on paper: Scanned the paper words and drawing into corel trace, and traced them on the centerline or outline if you want a two line image: zoomed in on each part and cleaned up the extra little lines the trace created: saved as a DXF file; opened file in Turbocad 2d freeware and placed it where I wanted on the plaque and saved as DXF file: opened in gcode 2000 to generate the gcode. Saved as a text file and cut the image and letters in Desknc. That was a labor intensive way. Now method #2 generate type in Deskengrave (freeware) save as DXF; open in Turbocad 2d combine with any artwork, size and reverse: save as DXF: generate gcode with gcode 2000: cut on router with desknc. There are much faster methods than I used but I already had the software and I didn't want to buy any new until I found out if these were going to sell around here- they did not so I didn't spend a lot of money to test with. Just my pennies worth. I will probably go download sheetcam and see what it's all about, sounds easier than my method. Ron

[Mr.Chips]

Benny, you'll be glad to hear that there is a Yahoo group for SheetCAM.
It's being written by the same guy who wrote the Keygrabber utility for Mach2. When you download it there are tutorials included. I played with it a little a while back, it worked pretty good. He's added a lot of features since I last looked at it. Anyone who needs a 2.5D CAM package should really take a look at it. He's filling the void of low cost 2.5D CAM.

Could you give us the link to that Yahoo Group for SheetCAM?

Thnaks
Hager

[The Wizard]

Could you give us the link to that Yahoo Group for SheetCAM?

Thnaks
Hager

http://groups.yahoo.com/group/sheetcam/

HTH,

Larry Green

[The Wizard]

Thanks for your info Ron.

That is somewhat similar to the way I did it. I was just playing around with ideas and was using the logo of a club I belong to.

I had the original in Illustrator and all text was converted to lines and the image flipped. When I exported the dxf all curves were splines and I then had to trace over it in my CAD program to make all lines closed polylines. I then used SheetCam to define the pockets and generate the G code.

My idea was/is to seperate the design into three layers with each layer engraved onto a seperate piece of acrylic. These will then be 'stacked' together in a base and be edge lit with either LEDs or 'glow-wire' so that the engraving 'glows' in different colours.

Larry Green

[foamcutter]

Larry,
Nice idea about the layers and different colors. I may just have to try that and see what it looks like. Ron

[ger21]

I had the original in Illustrator and all text was converted to lines and the image flipped. When I exported the dxf all curves were splines and I then had to trace over it in my CAD program to make all lines closed polylines.

Larry Green

Try exporting as R12 .dxf if you can. AutoCAD saves splines as polylines in R12 .dxf's, Illustrator might as well and this will save you a step.

[The Wizard]

Larry,
Nice idea about the layers and different colors. I may just have to try that and see what it looks like. Ron

I saw a website once that briefly showed how it was done but I forgot to bookmark it (DOH!) and now I can't find it again despite many searches.

Basically each 'colour' was reverse engraved onto a seperate sheet of Plexiglas and then the layers were sandwiched together. The edges were painted with black paint to contain the light within the sheet except for a small area directly above the LED for that sheet. When the LEDs were turned on the engraved areas 'glowed' in their respective colours but the sheets themselves remained clear.

I designed a 3D logo for the kite club I belong to and I had hoped to try this out as a possible trophy but I am having a few problems trying to generate the required G codes. I have attached an example of the logo but of course the colours would be different depending on what LEDs are available.

I have vector, raster and CAD formats of this but while I can get the text to look right using a 60° engraving cutter I cannot get the chevrons to cut correctly (bear in mind I am only simulating at this time as I still have to build my machine). If I use a CAD file the chevrons come out as flat with bevelled edges, if I use a raster file (converted to grayscale gradients) I can only get it in 'relief' and not as a 'pocket'. I have even attempted to model the chevron in 3D but not had much luck there either. I am trying to use several different software demo packages to get the results I want but so far it is eluding me.

I guess I need to play some more while waiting for machine parts to arrive!

Larry Green

[The Wizard]

Try exporting as R12 .dxf if you can. AutoCAD saves splines as polylines in R12 .dxf's, Illustrator might as well and this will save you a step.

I just checked and I can only export as R13, R14 or 2000 dxf files or as the same in dwg format.

However, I did open the dxf in my CAD program and I could save out as a R12 dxf in that and when I re-opened the file all splines were 3D polylines :banana: .

Thanks for the tip ger21 I will remember that one.....LOL!

Larry Green

p.s. I just checked the file sizes and was amazed to see the original 24kb dxf in 2000 format was now bloated to over 3 Mb as a R12 dxf......EEEK! On closer inspection I found that instead of a few points with polyline arcs (which is what I traced originally) I now had literally thousands of tiny lines instead :frown: ....oh well it was a good idea I guess!

[ger21]

I didn't realise you used polyline ARCS. When the splines are converted to polylines, they are just a LOT of straight line segments, no arcs. a polyline arc segment is basically the equivalent file size to a single straight polyline segment. They both use the exact same data. That is why your file size is so much bigger.

On the plus side, you don't have to do the tracing, and with todays huge hard drives, who cares how big the file is. And the multiple straight segment polyline may follow the original spline a little more accurately, but maybe not as smooth.

The only difference is you're machine may run better (faster, smoother) with the G2's and G3's than with a bunch of G1's. But then again, it may not.

[The Wizard]

I didn't realise you used polyline ARCS. When the splines are converted to polylines, they are just a LOT of straight line segments, no arcs. a polyline arc segment is basically the equivalent file size to a single straight polyline segment. They both use the exact same data. That is why your file size is so much bigger.

Yup......I understand that.

On the plus side, you don't have to do the tracing, and with todays huge hard drives, who cares how big the file is. And the multiple straight segment polyline may follow the original spline a little more accurately, but maybe not as smooth.

Well in my case file size would matter as I am planning to use a dedicated 'old' computer for the machine and the chances are it will only have a floppy drive for file transfers. If the G code file exceeds 1.44 Mb I would have to look at splitting it into sections and recombining them on the CNC computer.

The only difference is you're machine may run better (faster, smoother) with the G2's and G3's than with a bunch of G1's. But then again, it may not.

True......I guess I will find out when it comes to cutting time....lol

Larry Green