CNC project for beginner operators ( Horizontal twin cylinder)

[Tin Falcon]

I was in northern Jersey today for a job found myself near McMaster Carr so 20 minute wait and $XX later I have a 1/16 rounding bit and a couple of premium grade 1/8 carbide cutters.


Gary : I think if you want to use an 1/8 radius cutter you should be able to just edit the code run the cornering cycle twice and the second pass change the z. you should be able to do a little copy , paste and edit. But I am just learning too so if I am wrong please someone correct me.
Tin

 

[stevehuckss396]

Hi Steve

My 1/8" corner rounding end mill has a 1/4" tip.....would you please post the outline dimension's of the base(or the dxf) so I can redo that section of code.

Thanks

Gary

This took all of a minute and I cant post a DXF file.


View attachment BaseWith.250TipRadiusMill.tap

 

[kvom]

My experience is that corner rounding bits need to be "fine tuned", and the DOC may vary. One approach is to set Z0 a bit higher than the surface and run several times decreasing Z0 until you get the desired profile.

 

[stevehuckss396]

I was in northern Jersey today for a job found myself near McMaster Carr so 20 minute wait and $XX later I have a 1/16 rounding bit and a couple of premium grade 1/8 carbide cutters.


Gary : I think if you want to use an 1/8 radius cutter you should be able to just edit the code run the cornering cycle twice and the second pass change the z. you should be able to do a little copy , paste and edit. But I am just learning too so if I am wrong please someone correct me.
Tin

What will happen is the code being written for the .375 tip, the center of the tool will run .1875 offset from the edge of the part to round over the top edge. If the .250 tip mill is used, the tool will still be run .1875 from the edge so the tool will be .0625 from the edge. The depth will still be correct. I have rewritten the code for Gary's cutter so it will be held .125 offset from the the edge of the part.

 

[stevehuckss396]

My experience is that corner rounding bits need to be "fine tuned", and the DOC may vary. One approach is to set Z0 a bit higher than the surface and run several times decreasing Z0 until you get the desired profile.

I didn't go cheap (never do on cutters) and I just cut the depth of the radius and use the tip diameter as the cutter diameter in CamBam and I get a good corner.

 

[gld]

Thanks Steve

 

[Tin Falcon]

By Steve from post# 1 A 1/16 inch radius cutting endmill with a 1/4 inch tip was used to clean up the edge. If you don't have
this cutter and don't want to buy one, you could just leave the 1/8 inch endmill in and press cycle
start. The mill will go thru all the moves and when prompted for the 1/8 endmill again, it is already in
so cycle start again and you can continue having skipped the radius step.

from post #43 : What will happen is the code being written for the .375 tip, the center of the tool will run .1875 offset from the edge of the part to round over the top edge. If the .250 tip mill is used, the tool will still be run .1875 from the edge so the tool will be .0625 from the edge. The depth will still be correct. I have rewritten the code for Gary's cutter so it will be held .125 offset from the the edge of the part.

Ok the rounding mil I purchased is a 1/16 radius with a 1/4 tip so what code am I running for this ???
Tin

 

[stevehuckss396]

Ok the rounding mil I purchased is a 1/16 radius with a 1/4 tip so what code am I running for this ???
Tin

EDIT!!! The 1/16 rounder is for the Standards ( first pieces) so the original code is what you want. The base has a 1/8 inch radius.

 

[Tin Falcon]

so I need another rounding bit. There goes next weeks allowance :
Tin

 

[stevehuckss396]

This week is going to be the crankshaft. The shaft itself is made from 1/4 inch tool steel (drill rod) as is the
crank pins from some 1/8 inch. The crank disks can be made from anything you have handy. Steel, brass,
aluminum are all fine but I figured if i'm going to build a corian engine, I'm going to make the disks from
the same material.

I had a 8 X 2-1/4 inch piece but a 7 X 1-3/4 would be big enough. The spot drill, 1/8 and 1/4 holes are drilled
as usual.

I have 5 different thicknesses of material to cut. The thickness of the finished part depends on how far from
the bottom of the stock I cut to. I have to stop .188 inches from the bottom. I cant touch the tool off the
bottom of the stock. I could write a separate program for each thickness. OR! what I did was write a program
for a .500 inch thick piece. Now all I need to do is measure the actual piece. This one was .4775 thick. That
means that the surface of the actual piece is below Z0. .4775 - .5000 = -.0225. The surface is twenty two
and a half thou below Z0. I touched the top surface of the material with the tool and then in the Z DRO I typed
-.0225 and hit enter.

The pieces will then be cut to thickness and then cut out and drop right out the bottom. I made the program
take care of 4 pieces at a time. The thinking is that most people will make 2 or more engines.

Pretty darn close. just to recap

1) Touch tool to top surface
2) Measure stock thickness
3) Stock thickness - .5000 = Z
4) Type Z into the Z axis DRO and press enter (don't forget the minus sign for negative numbers)

I used my slotted piece for a drilling fixture. The slot was opened up to a few thou wider than the disk and a
1/8 inch pin was drilled in on center.

I was able to load and unload the disks quickly for drilling.

I then chucked a piece of drill rod into the lathe. The disk was put onto the rod and cut to finished size.

I tried to slip the drill rod thru the standards. It went thru the first one but got tight going thru the other one.
I chucked it in the lathe and polished it with some 320 grit until it was a nice fit. The shaft was then cut to
length. I measured the distance between the standards and added .389. The flats were milled into the shaft
to complete the job.

The crank pins were polished on one end to slip thru a 1/8 hole nicly and left to size on the other end. The big
end is then pressed into the disk. The disks are then installed onto the shaft with some 4-40 set screws.

View attachment Crankshaft.pdf

View attachment CrankDisk.tap

 

[stevehuckss396]

so I need another rounding bit there goes next weeks allowance :
Tin

Not really. You could always skip the step and leave the top edge square. If you want I could write you a custom code to give a 1/16 edge instead if the 1/8. Only take me a few minutes.

 

[Tin Falcon]

If you want I could write you a custom code to give a 1/16 edge instead if the 1/8. Only take me a few minutes.

That would be cool. Thanks for all the work you are putting into this. Hopefully one day in the not too far future I will be able to do all the steps myself.

As far as the crank disks go , In my experience a plastic crank dis is not the best way to go, I have made a few engines, Some of them have logged quite a few hours typically 8-16 hours a show 2 -4 shows a year some since 2003. the only engine part I had fail on me was a crank dick from plastic. I love Poly(methyl methacrylate) as an engine material both in the clear plexiglass form and the colored cousin Corian. I have made several engines with this material . FYI I have used brass pen tubes to line bush around the crank shaft the tubes are 1/4 ID and 7mm od.

Tin

 

[stevehuckss396]

That would be cool. Thanks for all the work you are putting into this. Hopefully one day in the not too far future I will be able to do all the steps myself.

As far as the crank disks go , In my experience a plastic crank dis is not the best way to go

If I were going to run them alot I would make them in brass. The engines will most likely end up on a shelf as a trophy as I am making them for the guy who supplies all the free corian. I'm guessing they will end up on his desk and run 4 times a decade.

Here is the custom base code. 1/16 radius cutter with a 1/4 inch nose

View attachment BaseTinSpecial.tap

 

[Tin Falcon]

I'm guessing they will end up on his desk and run 4 times a decade.

Then the corian is probably fine

Here is the custom base code. 1/16 radius cutter with a 1/4 inch nose

I thank you and my wallet thanks you. :bow:
Tin

 

[Tin Falcon]

Well guys I finally got up the nerve to hit the start button. I did my homework ran the program on the laptop to familiarize myself with it. ran the program a over the work piece(set the z 0 about 3/4 above the work) cut a little air. I cant say the attempt was a failure . It was a learning experience . It did not produce a usable part.
Some of the points learned. Remember to reset the z for each tool did it but had to remind myself
corian can be abrasive and jamb up the works put the way covers back on the mill.
this caused missteps and threw off the Zero points.
also if you think the cutter is pushed in tighten it up it is telling you it is loose nicely. if you do not listen it will pull out embed itself in the work and break off and possibly damage the collet holding it. did i listen to the hint NO and I paid. a new end mill broken. aaarg.
Steve: you did say post the failures so there it is.
Tin

 

[stevehuckss396]

Steve: you did say post the failures so there it is.

I happens to everybody. I hold my endmills in collets because they seem to hold better than a drill chuck. Also run your spindle as fast as you can. I ran mine at 4000RPM.
Also use the shop vac while you cut and all the chips are cleaned up as they are made.
Also try to Zero your tool at the same spot (roughly) on the work piece.
Also never buy just one cutter at a time. Saves alot of gas.
What is the max feed rate of your mill when you tuned your motors and calibrated your axes. I over motored my mill a little and am able to move 350 IPM without losing steps.
This is where you become one with the mill. You learn what it likes and what it doesen't like. Very important when you start producing your own code. Once you get going your going to love this stuff!! Hang in there.

 

[Tin Falcon]

I hold my endmills in collets because they seem to hold better than a drill chuck.

Yep did that guess I needed it tighter

Also run your spindle as fast as you can. I ran mine at 4000RPM.

the code said 1000 thought that seemed slow for 1/8 especially carbide now you tell me.

Also never buy just one cutter at a time. Saves a lot of gas.

Yeah I know I bought two wish now I got 3 . I need to place an order to Richon and order a dozen.

What is the max feed rate of your mill when you tuned your motors and calibrated your axes?

I do not remember I think I kept it fairly conservative the X2 has a 4x 8 work envelope so not far to go in any direction.


motors from HOMESHOPCNC are 300 OZ motors wound to match the G540/G20/g251 family.

Hang in there.

Definitley. I have been messing with this thing for 3 years now a bit there and there. Mostly building tinkering. I am not giving up know.
There have been times I have been tempted to remove the motors and put the handles back on. but this is not one of those times. in spite of not getting a useful part the first run in full cnc mode was fun . I do need to learn to listen closer and heed what the machine is telling me . it was talking I did not listen.

Thanks for your code and your encouragement.
My biggest concern now is whether the collet was damaged and if it will hold a new mill. I looks a bit deformed it is an er style
Tin

 

[stevehuckss396]

Yep did that guess I needed it tighter the code said 1000 thought that seemed slow for 1/8 especially carbide now you tell me.

That is my fault!! I control my spindle with a VFD. You can set spindle speed in CamBam but I dont fool with it. Default is 1000.

I have no idea what speed my spindle is turning. I adjust by the sound. Drilling is about 1/4 of max but the larger the bit, the slower i go. The same applies to cutters. The larger the cutter the slower the spindle speed. Like I said before, you need to find what the mill likes.

 

[GailInNM]

Well guys I finally got up the nerve to hit the start button. ........
Tin

Tin,
It gets worse when you are nearing the last operation, you have had 13 setups and have over 30 hours invested in the part. A simple "Ah shucks" will not cover the situation.
Gail in NM

 

[stevehuckss396]

It gets worse when you are nearing the last operation, you have had 13 setups and have over 30 hours invested in the part. A simple "Ah shucks" will not cover the situation.

Yeah but other than that, it's fun!! ;D ;D ;D