Messages

701

G-Code, CAD, and CAM discussions / Re: Milling parts from end of stock

« on: January 01, 2011, 11:41:12 AM »

Russ,

Good evacuation of chips is certainly desirable. I haven't investigated how they effect the tool life, but they sure cause an awful noise if not evacuated to clear the cut. Just hearing that noise makes you think it's going to break the cutter, so haven't had the courage to leave it like this for more than a few seconds

Dan

702

G-Code, CAD, and CAM discussions / Re: Milling parts from end of stock

« on: January 01, 2011, 09:10:49 AM »

Hi Russ,

Looks good.

If machine rigidity is not a problem, these end mills should do fine up to depth of 1/2 their diameter cutting full width.

If you can get a deal on some roughing end mills it would save you some money on the finishing ones which you want to keep sharp. Also roughing end mills can go as deep as their diameter on a full width cut. Carbide are best and are a good investment, especially when you have no coolant.

Dan

703

Show"N"Tell ( Your Machines) / Re: CNC Large Lathe Conversion pictures

« on: December 30, 2010, 02:17:25 AM »

Ah... OK. That makes sense. I was bothered with the Z axis as I said. Being 2.5" diameter, I see no problem Somehow I missed you saying the Z was 2.5" and it was only the X with the 0.75".

Dan

704

Show"N"Tell ( Your Machines) / Re: CNC Large Lathe Conversion pictures

« on: December 29, 2010, 05:06:24 AM »

Nice little lathe Amazing how well it's preserved. It's 70 years old and looks better than some 10 years old machines I've seen.

0.75" diameter ball screws..? Sounds to small for a lathe that will cut 15mm per pass. Would expect twice that. At least for the Z.

Dan

705

G-Code, CAD, and CAM discussions / Re: Milling parts from end of stock

« on: December 29, 2010, 02:02:39 AM »

Oh... one more thing. I am not sure how it works with G41/G42 offsets, so be careful if you're using them. Sometimes G41/G42 offsets don't like offseting of the coordinate system.

Dan

706

G-Code, CAD, and CAM discussions / Re: Milling parts from end of stock

« on: December 29, 2010, 01:59:47 AM »

Hi Terry,

Good idea as always! I like your productivity.

Russ, do as Terry suggests for a stock you have and then it is fairly simple to tweak the G-code to accommodate for future stock changes. Let's say you do your G-code for a 4" wide stock - bottom parts aligned with the bottom edge, top parts aligned with the top edge. Be sure you first cut all the bottom parts and the move to cutting all the top parts. Let's assume next time the stock you get is 4.1" wide. You align the bottom edge of the material with the bottom parts' edge and the bottom parts are fine. Now the problem is with the top parts. Use "G52 Y0.1" before the code for the top parts. It will offset the coordinate system by that amount. Program "G52 Y0" in the end to cancel it.

Dan

707

G-Code, CAD, and CAM discussions / Re: Milling parts from end of stock

« on: December 28, 2010, 11:53:15 AM »

What is the hole size? If it's big enough to put a substantial bolt in it (like 1/4"), then you're good. Bolt the stock down to a sacrificial plate (use enough for a pair like Sam suggested - you will have two bolts holding the stock), using the holes, then mill the profile leaving about 0.01" for the last pass - it is enough to hold the stock, but yet not to much to develop large cutting forces on the last pass, so the single bolt per part should handle it fine. Just tighten it firmly.

Dan

708

General Mach Discussion / Re: polished aluminum

« on: December 26, 2010, 03:19:45 PM »

Assuming your machine is up to the task, as mentioned above, 3-flute carbide end mills designed for aluminium work best. They have very sharp cutting edge and milling on the side I can get very smooth surface seeing my own reflection. Using a good cutting oil helps a lot with aluminium to get a good finish.

Dan

709

General Mach Discussion / Re: Making a tapered thread. Please help

« on: December 26, 2010, 03:10:10 PM »

The taper angle in your case will be:

tan^-1(((0.750-0.310))/2)/1.850)

BTW, cut a taper thread only once, couple years ago, and it worked fine with the simple treading wizard.

Dan

EDIT: Ha.. ha. You're quick Rich. You posted the answer while I was typing

710

VB and the development of wizards / Re: macros, Is this the way to do it?

« on: December 25, 2010, 01:18:12 AM »

You can use a subroutine right in the G code, like this:

test.nc
G01 X2 Y0
M98 P101
G01 X9
M98 P101
G01 X14
M98 P101
G01 X15 Y5
M98 P101
G01 X0  Y4
M98 P101
G01 X1
M98 P101
M30

O101
G1 A2.5
G1 A0
G1 A1.7
M99

Read the manual for more details.

Dan