Possibly a different approach to manual digitizing?

[vmax549]

Andrew try the manual DMM approach with Mach it works fine. It is easy to pickup all the major points and write down a few notes. Then all you have to do is connect the dots. You do not need a expensive probe, A $20 led touch probe from Enco will work fine. Mach will give you all the info, you just have to write it down Terry

[Ed_R]

Where can I find more info on the DMM approach and the $20 LED touch probe?

[vmax549]

Ed the manual approach has been around as long as DROs. You simply insert a probe into a circle, move +x until you touch, -x until you touch, divide the distance by 2 and return to that point. Do the same in Y and you have the center position of that circle. plus the last moves gives you the diameter if you apply the offset of the probe tip. To do a straight line you only need the starting point and ending point then connect the dots. On an arc you need the starting point ending point and the outer most edge or the arc and cad can complete the arc line ( or calculate by hand ) On all your points you need to note whether it is an outside point or inside point to know how to apply the offset of the tip. On the LED probe it is just a low cost electronic edge finder. When you touch the part a light comes on. (This only works on metal parts) Hope that helps. This is only effective on simple 2d or 3d parts. Terry

[Ed_R]

I think for what I'm doing that approach will only work for 20-30 percent of the surface. The rest is pretty complex curves and arc.
I have a headache.

[vmax549]

Ed how complex is your part? Have you tried taking a digital picture in grey scale and try to convert it. Sometimes that works quiet well. I use it to make cookie cutter dies.( don't laugh too hard). I take a picture and convert it to grey scale adjust the contrast and convert it to a vector drawing. It gives me a very good head start on Gcoding the part program. (:~)= Terry

[Ed_R]

That's a great idea, Terry. It's a top carve on a guitar, it has concave and convex surfaces in multiple dimensions, but I might have to try that.

[ViperTX]

Well guys it all has to do with resolution.......do you manually scan at 0.100 intervals when you're looking for 0.010 fineness......"Do you all get the pic....I'm sure you do."

[HansM]

I've been experimenting with the process of using digital photos or scans as a starting point for creating CNC sources. I have found that processing the image prior to the trace process is essential. I bring the images into Photoshop and use tools such as Threshold and Posterize to simplify them. Then I bring the touched up images into CorelTrace.

The settings in CorelTrace are important, too. I keep the "Complexity" and "Max Colors" low (around 9), and the "Node Reduction" at about 25. I do not think I have the process down to the point that I can accurately reproduce machine parts, but if pretty close is good enough I can go from a snapshot to cutting very quickly! Here are some images of a knife handle I am making from Rosewood right now.

Lance

[markm]

I dont know if this is the best idea I have ever had but what about a tablet pad to lay your part on and trace the edges and vectorize. You should get clean lines no yellowing or weird stuff from a scanner. I know a sign guy who uses his to do odd things like this for vynal cutting. Also the tablets are not to expensive.

[JFettig]

One way to do it(easiest on a manual mill with dro, but can do it on a cnc) is to set it on the mill table, indicate and pick a zero. then grab a center finder(pointy edge finder) and use that to find the centers of your holes, a little quick math and you can layout the whole part that way. Another way to do it is put dowell pins in all the holes and use an indicator and just indicate around them.

It sounds like you want a little more than that doesnt it


Jon

[Graham S]

You might want to look at scanners made by cannon, they don't seem to pick up anything very far from the glass at all.

A piece of tracing paper placed on top of the glass before the part might also help, I am happy to try this on my scanner, I have some excellent laser printable film for PCBs that makes and excellent diffuser material.

Graham