Trial Run

[snall]

I have spent a week now reading, reading, and reading differant topics on this forum. The amount of information here is overwelming. I will be buying a shopBot after the first of the year for producing 2d & 3d designs that my partner has {literaly dozens) made for his retail business. Since I do not have any CAD / CAM experience my learning curve is high but I don't see that as a problem in the 2d stuff. We will tackle the 3d items as we gain experience and the CAD/CAM classes give us a better understanding of the process. I am heartened by one botters statement "I can teach you anything you need with a $30.00 program and two days training for 2d work".

This is all building to something obviously but fist a little more info.
1. The demand for the product is there.
2. Other retail bussinesses have already stated that they would buy the products if only we could produce them.
3. We are not in a hurry because we want to do this right and learn as much as we can.
4. I believe that from what I have read that I will get some honest anwsers here on this forum from some honest people.

Now the question is:
I have one design drawing that is 2d that I would like a botter to analize and give me an honest anwser as to the following:
1. what amount of cutting time it would take to produce it.
2. Computer time to convert from drawing to .sbp file.
3. figureing tool paths and bits needed
4. etc, etc. (I'm sure there is even more that I dont know).
5. We will be cutting them out of 3/4" oak and Mahogany.
We can throw numbers at each other all day long but having this info on one of our more simpler designs would help us in figureing the wholesale costs on most of the 2d stuff (after the mistake and learning curve start to flatten out).
Is anyone intrested? It seems like some of you guys follow these threads just to find tricky problems to solve just for the mental exercize.This, I'm sure is like taking out the garbage for most of you.
At this point I am ignorant of almost all aspects of the cnc details. Shop bot is sending sample software (partwizard) for us to play with.
Any feedback good or bad would be helpfull.
Scott

[jay]

Scott, I looked for a CNC machine for about a year and have had a 'bot' for 3 months now. All I can give it is praise. Every time I thought the machine was not working right it has always been operator error.

Drawing 2D in Partswizard is a lot easier if you have some experience in working with a vector based program like CorelDraw, etc. the learning curve without that experience is not that bad. I like you wish I had some experience with CAD but that will come in time. The machine will cut exactly what you draw. I know from experience.

Converting to a .sbp file takes only a moment, you are not looking at hours.

Tool paths often are common sense. Not hard to do and again, depending on the speed of the computer, do not take much time for a simple 2D file. Cutting 2D does not take a lot of time either, as an example, I had 30, 5 1/2" hearts cut out of 3/4" Oak in less than 30 minutes using a quarter inch spiral down cut bit.

The working principle of CNC machines has not really changed in years but the software to run it sure has. CNC's can only do what the software tells it to do. Seriously consider upgrading your software from Partswizard to something like Artcam Pro or Profile Lab. It is well worth the time saved in frustration down the road. I know it is a lot of money but I can not over emphasize good software.

If you want to email me, feel free to do so. Just click on my name at the top of the message.

[gerald_d]

Scott, you said "Is anyone intrested? It seems like some of you guys follow these threads just to find tricky problems to solve just for the mental exercize.This, I'm sure is like taking out the garbage for most of you." Well, my real job is to take out the garbage, so please send me the file.

[snall]

Thanks all. I have had several offers (in just 4 hours) to look at this for me and I appreciate the support. This item has more detail than a simple cut out but it is also one of our more basic designs. I am looking forward to joining the Bot community and also comparing the different ways that each person will tackle and solve this "favor" that I have asked of them.
G- South Africa is a long long way from Alaska.
Nice to meet ya.
Jay, Things for the support. Its people like you that make us newbies walk forward with a little more confidence.

Scott

[gerald_d]

Yes Scott, we are a long way from Alaska - the furthest point from us, on the other side of the globe, is near to Hawaii.

Thanks for the picture via e-mail. To be quite frank up front, this type of job we turn away and send the clients over to the fretsaw people. We won't through-cut 3/4" material with a smaller than 1/4" cutter, and a 1/4" cutter won't give you anywhere near the detail that you want. Sorry about that.

[snall]

G
what about using a v-bit to scribe in the detail to 1/4" on both sides and doing away with the through cuts?

[gerald_d]

Ah, now you are talking something that is lot more practical and economical. But, what do you think should happen to the outside profile?:
- Accept that all detail of inside corners will be radiused? or,
- Cut with radiused corners, and then "sharpen" the detail with a bandsaw or jigsaw? or,
- Cut a large oval blank, and inscribe the whole pattern with a V-bit cutter? (which puts you in a smilar category to the Asian breadboard makers who charge $2-$3 per board)

Essentially, your concept product is best suited to fretsaw methods and not to a router. If you compromise the design of the product to suit the machine, will you still have the projected sales to make it viable?

[barrowj]

Scott, i would be interested at looking at your design. It sounds like something i have done but not sure.

[snall]

G,
Yes on all points except that the outline needs to be cut out. Finisihing up with a fret cutter shouldn't be to big a problem. This includes the cut outs on the inside also. If we use a 1/4" bit to cut out what we can then use the fret saw to clean up the "points" would we still get too much time involved. Right now it takes about 1 3/4 hour to finish one out with a saw alone. any improvment on that would be significant.
Keep the ideas comming.I'm having fun trying to come up with solutions to the problem.
Hey shopbot!! any ideas on this!
Scott

[mrrecycler@aol.com]

Scott
Thought Id jump in. Could you cut the design with a 1/4 bit then clean up with a smaller bit? Ive never done it with 3/4 inch material maybe someone else has. I know you can get bits down to 1/32 with a 1/2 cutting length so you could clean up in 2 passes( although at that small dia. the may flex). Has anyone tried this?
Kevin Reid

[snall]

Kevin,
I really can't anwser your questions. I don't have my Bot yet but what you say makes sense. The anwsers to your questions are what I'm seeking.
Jay, did you get the file I sent?
Scott

[gerald_d]

Yes, you can use smaller bits to get finer detail, but not at an economical price for "mass-produced" decorative work. The small bits remove material far too slowly, and they are prone to breakages if you try to push them any harder. A fine saw blade is much more efficient for this type of detail.

Let's change tack for a while. . . . . . . . .

Scott, your source information is scanned pencil/pen tracings done by hand and then scanned to produce a .jpg file. Here is a small part, approx. to scale, of the file that you sent out:


2756

The shaded parts are solid 3/4" hardwood.

You probably want the ShopBot to produce a smoother cut than your hand tracing and this means that you have a lot of CAD tracing and touching up to do. Can you get your designer to work in a more CAD-friendly way? ie. To design in Coreldraw, or other software packages, that will give you .dxf output of lines that are smoother, and that join up neatly at the corners, etc.?

[snall]

G
The designer wants nothing to do with a computer drawing system. He really does have to much on his plate anyways. Yes the smoother cuts are all desirible but that will be my job. I ain't complaining though. We are hopeing to keep these at under 10 minutes bot time per unit so cutting slowly with smaller bits in the corners after a 1/4" cut through (to .001 - .002) would be acceptable. Finisih up with a scroll saw.
S

[artisan]

Scott...At first glance, it looks like you could accomplish 90% of your profile cuts with a 3/16 bit. This will require 4 passes of the tool , however, and will take some time. Gerald's point about redrawing in CAD software was not made strongly enough, I think. If you use a tracing software, the Bot will pick up EVERY nuance and detail of all the "squiggles" in your drawing and will be slowed "tremendously" as it tries to faithfully re-create your drawing. You should use this time to learn a CAD product or Draw product like Corel or Turbocad while awaiting your machine. The Shopbot....for all it's remarkable usefulness...simply follows the "marching orders" that you give it. I really believe that your strongest gains in economy will come from beginning the learning curve of your software of choosing. Otherwise, you could perhaps offer to contract with an accomplished Botter to convert your drawings in the meantime. Give a man a fish, he eats for a day....teach a man to fish... Best of Luck....D