Messages

21

G-Code, CAD, and CAM discussions / Re: Parabolic Dish

« on: January 11, 2017, 11:39:39 PM »

Gary,
Actually what I posted wasn't entirely accurate. When MeshCAM Art created the tool path, I omitted the roughing tool path. And instead, used the tool path it had created for the finishing cut. (Even though I had specified 1/8" end mill as the cutter, I actually used a 1/4" end mill as the cutter). It turned out really smooth, and it took a total of 10 minutes to cut. I apologize to everyone, for lying about what I did. It is something that I frequently do, as far as the machine is concerned (lie about tool size). It actually produces some interesting results, to do this (IF one is willing to accept the slightly smaller carving, that results from using a cutter with a larger diameter than the diameter specified when the tool path is generated). The reason, is to produce a carving with the greatest amount of detail. By specifying a smaller diameter cutter, a more detailed tool path is generated, than is possible when specifying the actual diameter of the cutter used.
Again, THANKS everyone!
-Michael

22

G-Code, CAD, and CAM discussions / Re: Parabolic Dish

« on: January 10, 2017, 05:09:35 PM »

Thanks to everyone for all the advise. However, I have since solved my problem. I used MeshCAM Art to carve the dish.
I simply drew a 3" diameter circle, and colored it black. Imported the bitmap image into MeshCAM Art, and used the Shape Editor with the following specifications:
Shape: Round
Angle: 33 degrees
Starting Depth: .01"
Height Limit: No Limit
Subtract.
Then generated the tool path, using a 1/4" endmill as the roughing tool, and a 1/8" endmill as the finishing tool.
The result was a dish with a depth of .556" at it's deepest point (center of circle), which feathered out to zero around it's perimeter. Works for me, this cut was used to create a "funnel" which is used to guide a pinball into it's return trough slot. I was already aware that MeshCAM Art could handle it. I was simply curious to learn the math involved in manually coding such a cut. I did attempt to use the Newfangled Wizard for a circular pocket. However, there do not appear to be fields available to control the cutting depth other than a flat bottom cut. I did try editing the resulting g code, to plunge the Z deeper between each pass. Which did a pretty fair job. But it was a spiral cut, which resulted in a "threaded" spiral, in the surface. As opposed to the desired smooth slope I was looking for.
Again, THANKS everyone!
-Michael

23

G-Code, CAD, and CAM discussions / Parabolic Dish

« on: January 09, 2017, 06:42:22 PM »

This is for the more advanced g-code wizards: Can anyone post an example g-code program to cut a parabolic dish?
I am not (yet) familiar enough with the g code command set to accomplish this. Even just a small, six inch diameter program would be helpful in learning the math involved. I know that it is possible to cut a ramp. Having tried this last night:
M3
Z0
X14 Z-.25 F6
M5
results in a groove which tapers from the stock's surface, to a depth of 1/4" across a span of 14 inches at a feed rate of 6 inches per minute.
What I am looking for, is similar g code for cutting a circular pocket. With a starting depth of 0, a center depth of .5 inches, and a finishing depth of 0 (at the opposite side of the circle). I.E. a DISH! How would one express this, in g code? I know that the machine is capable, I just ain't smart enough to communicate to it the steps such a cut involves!
HELP!
Thanks in advance -Michael

24

Competitions / Re: Win my Complete Collection of Cut Ready CNC Design Work ($1000.00 value)

« on: December 18, 2016, 11:21:03 PM »

Here is a picture of my second attempt at carving a 3D face sculpture. (The first was one of my wife, who has forbid me from showing- she is ashamed of her excess weight!!)

25

Share Your GCode / Re: Total Newbie biting off more than he can chew

« on: December 18, 2016, 10:52:30 PM »

I work with Corel Draw for most of my carvings. (profile cuts in particular, imported into LazyCAM). The DXF file format just doesn't work for me. So after many hours of trying different files formats, when exporting them from Corel Draw, I discovered that the Hewlett Packard Graphic Language *.PLT file format is the one to use. As it preserves the correct aspect ratio, and actual dimensions of the drawings. When importing them into LazyCAM. (Instead of just clicking the "open DXF" menu item, click on the "File, Open vector file", and select the HPGL *.PLT file format, then navigate to the folder where your file is stored, and click on it to open). Works great for me. And has for the past 8 years!

26

Show"N"Tell ( Your Machines) / Re: Router/Mill Design & Build

« on: May 14, 2016, 02:49:37 AM »

Regarding the ballscrew hardness. The way that I dealt with my machine (actually an acme lead screw, instead of ballscrew), was to place the lead screw into the 3 jaw chuck on my lathe. Then locked the headstock, to prevent rotation, and used a cut off tool, to scrape a slot in the end of the lead screw. The slot was cut to match key stock which matched an existing slot on the motor coupling (in my case). It could have just as easily been a drive pulley slot (as in your case). The key slot cut into the lead screw was not cut all the way to the end of the lead screw. Which provided a "tub" slot for the key stock to be seated into. Once the motor coupling was assembled onto the lead screw, a transfer punch was used, to mark the center of the grub screw hole into the key stock. Then it was disassembled, and the key stock was drilled at the screw's center, to provide a Secure Grip of the grub screw of the motor coupling, into the detent drilled into the key stock. The key stock being seated into the "tub" slot of the lead screw prevents ANY slippage from occurring end to end! Tip: if you don't have a carbide cut-off tool for cutting the ballscrew, try mounting a Dremel tool with an abrasive wheel into the tool holder of your lathe, and cut the slot with that! It works, no matter how hard the steel is!
Good luck on your build. Looks like you've got it going on!

27

Show"N"Tell ( Your Machines) / Re: Seeking guidance on router-lathe automation project

« on: March 25, 2016, 03:36:42 AM »

Mach 3 can control up to 6 axis of movements. (XYZ and ABC) How you build your machine, will determine the amount of control you can expect Mach 3 to handle. If I am interpreting correctly what it is that you have in mind (two routers on sleds which travel along the lathe bed) you will be somewhat limited in what you can automate.  (Ideally, 3 axis of control for EACH router would be best). But since Mach 3 can only handle up to six axis, this would mean the "platter" would have to be under manual control. Or at least one axis of control would have to be manual on one of the two routers. However, if you construct a 4-axis mill table, with a lathe along one side of it, you would have all the control you should need, using only 4 axis of movements! I designed, and built a 4-axis machine. Which does pretty good, however a word of advice: invest in a photo-cell and laser type of homing switch for the 4th axis (lathe axis).
 Because mechanical contact switches of any kind will beat themselves to pieces with use, and are just not very accurate in terms of consistency when homing the 4th axis to zero. This is just the machine side of things. For the "synchronized" subject, this will depend on your CAM software, and the tool paths generated by the software for use in Mach 3. Since you mentioned that you are an experienced CNC user, I am sure this is probably nothing new for you. The G code will determine what tool movements/work piece movements happen when (in order to "synchronize" things). Even though you mentioned using two routers, the reality is that a single router cutting on a work piece in the lathe jaws of a 4th axis, WHILE the 4th axis is rotating, will have plenty of work to do (which exerts quite a strain on the drive system of the 4th axis). A second router, also cutting on the same work piece, would probably be too much for the 4th axis to handle (unless of course, you construct a monstrous drive system for the 4th axis $$$$). You mentioned using Arduino, and Actuators as drive mechanisms. If you intend to place your machine under Mach 3 control, I would recommend using either stepper motors, or servo motors and lead screws (or ball screws) as the drive mechanisms. Folks tend the think that "just using a machine to cut wood" doesn't require very much torque, or power. Which is probably true, IF you are cutting Balsa wood!
 But for all other types of wood, you need POWER, RIGIDITY, and ACCURACY if you want repeatable results! I used NEMA 34 stepper motors, rated at least 900 ounce inches of torque with 5/8" diameter 10 threads per inch lead screws, driven by a Gecko G540 controller. If you are truly committed to building you own machine, a word of advice: Start NOW writing your "Owner's Manual", and begin recording ALL information in the book. Design drawings, actual dimensions, parts, materials, component specifications, where they were obtained. Also any alternate suppliers. (There will come a day, when these parts wear out, and are in need of replacement- it is good information to include in the Owner's Manual for your own easy reference). Also include Part numbers for things like bearings and belts. Thread sizes, and such for every nut and bolt used to construct the machine. All materials used.
 Screen captures of configuration screens for all software used (especially Mach 3). A well organized, and written Owner's Manual can be almost as much work as actually building a machine. But it is time well spent for your own reference. And can make the difference between selling your machine, or hauling it to the scrap yard, should you ever decide to part with it in the future. Good luck on your build! Have a blessed day! -Michael

28

Show"N"Tell ( Your Machines) / Re: Router/Mill Design & Build

« on: March 25, 2016, 02:36:56 AM »

Your design looks like it would make a good machine. But a word of advice, since you are building your own: start TODAY writing an Owner's Manual, and list everything you do, as you go. The sources you used for all parts, and components, as well as the drawings you have done, with actual dimensions of each component. Trust me on this, in the future, you will be glad that you took the time to create the book to refer back to. You should include screen captured images for all software settings, so that you will have all of the information readily available to refer back to, when making any future changes or upgrades. Good luck, and have fun!
-Michael

29

Building or Buying a Wood routing table.. Beginnners guide.. / Re: Help with ports on mach3

« on: February 09, 2015, 06:35:28 PM »

If the PC can run Windows XP, and if the PC is equipped with it's own (built-in to the mother board) Parallel Port, then I would recommend purchasing a G540 controller card from Gecko. It will be neccessary to do some of your own wiring, but you should be able to get it running under Mach 3 control.
Things you will need to know:
Motor type (Stepper or Servo)
Voltage ratings for each motor
Ohm readings for each coil of each motor (stepper type motors)
Whether the motors are Unipolar or Bipolar motors.
If you can obtain all of this information, and post it here, you may find that others can help you to get things going. For this is the very first information they will need to help you along your path. Unfortunately, there are just so many variables to all of this, that it does require a certain "Process of elimination" to even begin to help someone.

30

Building or Buying a Wood routing table.. Beginnners guide.. / Re: need help please

« on: February 09, 2015, 06:26:44 PM »

I can't comment about the PC, or operating system you are using. I am using an older Dell model running the XP operating system. The motor controller I am using is a Gecko G540 (supports up to 4 axis's of stepper motors). I am not at all familiar with the chinese router you are referring to. But it may help you to obtain help from the user group, if you could list some of the particulars about the chinese router. (Stepper, or Servo, number of wires to each motor, voltage rating, etc.)