Router/Probe

[cbradshaw]

I would like to know what type routers are the best to use. Do I need the Electronic Porter Cable?

Also, What do you think of the 3d probe .

Carroll

[birdsofplay]

I believe that a variable speed router allows more control and options over "Speeds and Feeds".

Depending on the variety of materials and jobs that you intend to pursue you'll need options.
Skimping on machinery is not usually beneficial in the long run.
You'll appreciate reliability when orders start to stack up.

The PC 7518 is a workhoarse and fairly inexpensive to have refurbished when the time comes.

[cbradshaw]

Does anyone out there have the 3d probe?. Do you like it?

Thanks,

Carroll

[Gerald D]

My impression is that the 3D probe is only 1D, ie. only sensitive in the z-direction. It seems to rely on the ShopBot and software to sample heights on a fixed rectangular grid.

I don't think that it has the capability, for example, of finding the bottom of a groove and then staying in the groove while digitizing its direction and length.

The fact that no photo has appeared on the ShopBot website yet is also a little worrying.

[davdallen]

the probe will sense contact in the x and y directions. whether or not the probe will follow a grove, depends on the program you write to control it. the probe is actually the same as the one I use on my MaxNC.

one nice feature is the interchangeable tip. you can make a tip the same size and shape as your cutter, that provides automatic tool offsets.

da

[Gerald D]

Please correct me if I am wrong, but I believe that the probe only senses contact . . . .period. It is not intelligent enough to know in which direction the contact is. If the probe is descending into a valley and it contacts the right hand side wall, it does not know which wall it touched. It would not be able to tell the software that it must go left before it can go further down. The probe has the same intelligence of a wire touching a conductive surface - it cannot tell in which direction the surface is sloping at that point, or what the angle of slope is.

The probe being offered by ShopBot is certainly not inferior to any others being used by the "professionals". However, we must have realistic expectations of the results that can be produced. The probe software can be downloaded from the ShopBot site - suggest you run this before you commit yourself to a purchase.

[garbob]

I have one. Used as a test once. You set the criteria to scan. I used it to scan the bottom of a stamped metal ashtray at .1 inch offset, each scan line is .1 away from the last. Cut styrofoam using code generated. Was rough, to be expected. Minimal finishing would give good results. I lied, I also scanned my table. Used a 1/8" probe. Works well. Need more practice. It does not have the ability to differentiate slopes running at 90 degrees to probe direction. Very similar to cross sectioning a roadway in surveying. Very time consuming. Very low cost compared to thousands of dollars for others.

[davdallen]

it does sense contact. usually that contact is the result of moving the probe in a single axis. if you move along the x axis and sense contact, you know you can't move in that direction any more. to follow a curve, you develop a program that moves in the x until contact, then the y, then the x, then the y, etc. to follow a slope, you need to test the z axis as well.

this requires that the programmer be smarter than the switch, which is why I'm not using it more.

once the windows dll is available, I'd like to try and use a camera and a line from a laser to acquire height maps.

da

[cbradshaw]

Thanks to everyone for responding to my "probe" question. This forum and its members are great!!

Thanks,
Carroll

[fuzzygrub@sinclair.net]

FYI After approx. 2000 hrs of probing 2.5d models
of various fish, (chinook), I've come to the conclusion that the probe and software available, not to mention the timely tech support, are very well worth the money spent. You must relize the time it takes to probe an accurate model and then cut it though. A 2.5d model 56in x axis 26in y axis @ .005x .0025 y could take almost a week to probe and 28 hrs per pass to cut, but the results are very satisfactory and you will have the file on disk. Good luck Carroll and get the probe, Keith

[Ted Hall, ShopBot Tools]

Well gee, we're suprised about the interest and questions ... and will work to get a picture and more info on the web site soon ... perhaps a video clip.

The comments in the top part of the two sample probe files in the ShopBot folder provide some insight on how the probing process works, and what can and cannot be done with it. But here's a bit more.

Gerald is right in suggesting that the probe is a simple switch. That it is ... but let me elaborate a bit. As indicated in the S_probe.sbp file, the quickest and least expensive probe you can use is a straightened paperclip, probing something metal. This will work well and has some of the same features as our 3d probe. The next type of probe you might imagine, though, is a simple micro switch with some sort of stylus. Such a switch can only sense something when it contacts from above, but is very inexpensive too. The S_probe.sbp file is designed to show you how to use such a switch. This file is a little inefficient, because to use such a proble you have to pull up to the full clearance height (the highest part of the object being probed) before moving over to do the next probe/plunge.

What makes our probe different from this type of simple switch is that it will sense contact in any direction (ie. from the side), not just from a verticle plunge. This means that this probe can scan (more closely follow the contours of) a shape. Probing still takes time, but using this sort of scanning approach is much faster. This is what S_prb3d.sbp does.

Our probe is not really "our" probe, but a clever little device that was developed and is made by the MaxNC guy. We just resell them. A touch of this probe from any direction will trigger the switch. Realize that the switch is not smart ... it does not know where the touch comes from. But the controlling file, because it does know how the probe is moving, does know where the touch comes from since you bump into something only in the direction you are moving. Thus, this probe -does- follow contours and -does- go right up and down (with some constraints for avoiding little protrusions) the sides of a valley.

The one confusing thing about this probe is that it is a 'normally closed' switch, rather than a normally open switch (necessary for the smart way that it works; and it also gives the software a way to check for the presence of the probe before starting a probing session). That means that the two sample probe files are not interchangeable between probe type without editing (ie. the S_probe.sbp file is for a normally open microswitch or paperclip; the S_prb3d.sbp file is for the 3d probe that we sell ... though it could be edited for normally open to use with a different type of 3d switch or for efficient paperclip scanning).

And, I should also indicate that during the fall we had some quality problems with the connections in the 3d probe (if you have any problems with an older probe that might be wiring related, you might call us for tune up instructions). However, since the beginning of December, we have been assembling them all ourselves and I believe the wiring is quite robust.

[mechtron@iafrica.com]

People who are new to CNC manufacture sometimes have a very high expectation of a "3D probe". I have privately been asked the question: “"why can't I just use the probe instead of learning programming. Surely I can just show my chairback (pegboard, signboard, maze) to the probe and then ShopBot will cut 10 pieces an hour?" The posts above make it very clear that this is not the case!