Machsupport Forum
General CNC Chat => Share Your GCode => Topic started by: Jammerm on August 02, 2012, 10:03:49 AM
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Since I've got my machine working, I was wondering where to start to make patterns for machine parts. I don't have any of the fancy programs for creating parts. I have used google sketch-up and I did find a deal on an older version of Turbo-Cam Deluxe. Still going through the tutorials.
Here's the first part I want to try, looks pretty simple. I would like to make a matchplate with six to eight parts on it. Then use it to cast the parts in Cast Iron. This is a drawer pull for an old printing press. Later I hope to do treadles and other brackets that get lost or broken. I can use this part as a pattern, but i would like to use my CNC to assist in making the part. I just need some guidance on how to get started. Hopefully this will be helpful to others who aren't sure about the whole process. Thanks!
Front and back..
(http://i183.photobucket.com/albums/x310/Jammer_55/Someday%20Projects/IMG_0090.jpg)
(http://i183.photobucket.com/albums/x310/Jammer_55/Someday%20Projects/IMG_0091.jpg)
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This will be a learning experience for both of us. I have been a patternmaker for 44 years and have made 3d parts and g code for mazak milling machines. I am trying to make my mach 3 cut a part that I made in Weber Synergy. This is the first thing I have tried to cut,but not too much luck so far. You can make that part using 2d paths and a corner rounding tool. Cut the outside and inside shapen and then cut the corners.
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I didn't get very far, I drew the pattern on turbo-cad and tried to generate the g-code. When I went to cut the part, all I got was the outside oval and the screw holes were in the wrong places. I generated it with lazy cam. I'll work on this more later, but for now, I'll use the part I have as a pattern and cast several singles. Hopefully I can get some good ones to make up a gang pattern for 6 to 10 pieces at a time.
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I do not know how turbo-cad generates gcode,but itsounds like you are doing well.
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Ha, Me neither.. I drew the part and opened it in Lazy Cam. I made a G-code but wasn't very good. I'm trying to learn too much stuff at one time. This old dogs a little slow.
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I have tried to use Lazy Cam myself and was not able to master it. I currently use Vectric Cut2d which is inexpensive and easy to use. I bought a copy of Bobcad and did not master it either. I draw complex shapes on TurboCad and transfer them to Cut2d to generate the g-code.
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Shouldn't be that difficult - I know; Famous last words. Probably right up there with, "Hold my beer and watch this!"
But, would like to give it a try. Need some measurements. Center - to - Center of the two mounting holes and their diameter. Distance top to bottom of ellipse, Distance edge to edge of ellipse. Diameter of center hole and the thickness ( width) of the of the circular surround. If you plan to cast; How thick do you want the base to be.
I do have another life, so don't expect code tomorrow! ;D
Bob@BobsShop
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Center to center - 1.5" mounting holes .125" Dia. The holes can be left out with just an indicator for drilling.
Top to Bottom - 1.45"
End to end - 2.0"
Center hole - 0.72" Dia. Outside of the Torus 1.16 Dia.
Flange thickness - .146
The torus is split and half on top of the flange and half on the bottom but the outside of the bottom isn't rounded over, it has a square shoulder like a washer to fit in a hole in the drawer. The inside shoulder is rounded. I don't know if that shows very well on the picture.
I had drawn the two .5" Dia. circles for the ends and snapped an arc on top and bottom. Created and the torus placed it on top with the center hole. The g-code generator didn't show the torus or the hole. All I got were the outside and 2 small holes.
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Attached are three files:
The DXF file was drawn in AutoCad Lt (2008) could have used a newer version, but it is the one I use most often.
The LCAM file was created from the DXF. LCAM is not my processor of choice, but since that is what you are using I went that way.
The txt file was created by LCAM. I added notes to the original tap file and re-saved it as a txt file. If the dimensions look to be to big it is because the outer edges of the ellipse are offset to account for the diameter of the cutting tool. I used a pocket for the inner circle rather than just cutting the diameter of the circle. Not sure but maybe I should have made the depth deeper (used .146 as the depth).
Note that the crowned torus was created using a .25 diameter ball end mill. Doubt you could find a .22 mill. The larger diameter will impact the edged of the center cut out slightly.
In order to create the flat torus you will need to make a separate tap file using a .25 flat end mill. That male flat torus would have to be attached to the the completed male product.
I don't do any type of mold work so I am not sure what I have created will even be of use to you. Nonetheless, it was an interesting project to play with.
Good luck. Let me know how your project turns out.
Bob@BobsShop
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>:( OOOPS!
Noticed at least one mistake in the code (and there may be others!)
Steps that the end mill steps over when pocketing from .3 percent to 50 percent. Makes a large difference in the number of milling steps. Revised file is attached.
Bob
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Had a BFO (blinding flash of the obvious) when I woke this morning. I gave you code for making a cutout of the part rather than coding a female mold. Like I said, I have never made molds. Let me know if you can do anything with the dXF I sent you or if you want me to recode for a female mold.
Bob@BobsShop - back to doing what I sort of understand ;D
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No, you were correct, I want the pattern of the part and not a mold. I'll make the patterns in wood and use the with Petrobond sand for casting. Hopefully I can gang about a dozen together on a matchplate.
I am a total newbie to this side of things, so most of what you explained made no sense to me at all. I'm sure I'll have several BFO's when I get to the shop to cut this. Thanks so much for the code, hopefully this will give me some insight on how to do this myself. A community is great for helping each other out, but I also want to learn to fish so I can feed myself. I know I need some newer software, I'm just trying to decide what will work best for me before I throw a few hundred dollars out there. Metalcasting is my main obsession, I just want to use CNC for making patterns, parts, and some signage.
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Ok, I did a quick cut in a blue foam piece. Mounting holes are perfect, I drilled them with 1/16" bit. The center hole is good, but it cut the torus in the negative instead of positive. I need to take a picture of the edge so it shows up better. Looks way better than what i was cutting anyway. The elipse did look way too big but, you're right, when it cut it was fine. I'll try to get some pictures, this is all pretty cool stuff!