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Author Topic: CNC lathe  (Read 9951 times)

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Re: CNC lathe
« Reply #10 on: May 09, 2007, 03:37:56 PM »
Roberto,

Did you get your lathe yet?

Dan
Re: CNC lathe
« Reply #11 on: May 09, 2007, 04:17:58 PM »
Dan, the lathe has arrived in town and will be delivered to my house tomorrow.  It will probably be a few days to
get it going and check it out.

Bob
Re: CNC lathe
« Reply #12 on: May 09, 2007, 04:43:40 PM »
WooHoo let us know... I wouldn't be able to do anything else till I got it running....
Re: CNC lathe
« Reply #13 on: May 09, 2007, 05:58:25 PM »
Yes,  I will be at it as soon as I get it.  I installed a subpanel so there is plenty of power available, but it will have to be wired up..,.Then I will have to get familiar with it and see how it goes.  I have had the Mach3 program for a month and have written some sample programs, so it will be a matter of learning if they work as well in reality as they do on the computer screen.
Re: CNC lathe
« Reply #14 on: May 18, 2007, 01:34:33 AM »

Well, I have had the lathe a week and after getting it set up in my garage, I finally have been able to play with it.  It is very solid, weighs about 450 pounds.  It took myself and four friends to lift it on the bench.  But having that weight it is very rigid for a benchtop.  I got the very first lathe they shipped out and as such they have not had a chance to write a manual for the CNC part.  There is a manual for the standard lathe.   But, Richard Lowe has been extremely helpful and I have made a number of calls and he has helped me out a lot.  To answer the comments of DAlgie,  the ball screws are completely covered with metal covers.  I think they had them uncovered just to show for the pictures.  The x axis stepper does stick out a little but it is not as much as it seems in the pictures.  It causes no problems.  The appearance of the lathe looks every bit as good as the pictures and seems to be very well made.
One of the things I learned from Richard was that you have to be sure to take off all the packing grease off the ball screws before operating.

Again, Richard sent me a profile for this lathe that he wrote to install in Mach 3. i did a few small cuts on Aluminum and was very impressed with the  smoothness of the surface.  It has a 1.3 hp motor and so has plenty of power.  I tried a .100" cut and it handled it with ease.  I haven't tried, but Richard says he has taken .050" cuts in steel, with no problems.  I then wrote a small program to cut a hemispherical surface of 1.25 " diameter.  It worked well and gave a beautifully smooth  hemisphere.  When I went to run it again I found a little glitch.  On making the fast traverse the Z stepper motor stalled.  On checking with Richard he helped me to adjust the velocity and acceleration of the Z axis.  It was set a little too high and also he thought I should adjust the Gibs as the Chinese tend to have them pretty tight for shipping.  After playing with this a while I found good values for velocity and acceleration that worked well.  Then I started checking for accuracy of cuts and found they were off a little.  So another call to Richard and he told me I have to tune the stepper motors.  ( I am new to this game and didn't realize this).  So he helped me.  There is a formula in the Mach turn manual that tells you how to calculate the values for z and x.  So we calculated and tuned the motors.  This gave more accuracy, but not good enough.  So you can check the values by putting on a good dial indicator and then do it by trial and error.  After Playing around with this awhile I again came up with good values that gave good accuracy. (Generally within .0005 to .001 inches in both the x and z movements over  a 1 inch travel.)  I think the reason that the calculated value  was not as good as it should have been is that we were not sure of the exact value of the pitch of the ball screws.

So I wrote another more complicated program that bores into a 1.1  Inch piece of Al and has a 20 degree taper inside that goes in from x=.902 for about .   .350 and then makes several steps going to smaller and smaller diameters.  It came out really nice.  The surface on the very inner steps was a little rough because I was using a small diameter boring bar and took a little too big of cuts to do the finish.

So, overall I am very pleased with the lathe so far. I found out that this price of $3499 was an introductory price for this first shipment and after that the price will go to $4495. As I use it some more I wrill write in and let you know how it goes.

As an aside I got a call today from a company I had checked in with several months ago on getting a Dynamite lathe.  He said it was only $45,000!  When I told him I got a new CNC lathe for $3499, he didn't believe me.  Of course mine is not nearly as sophisticated as the Dynamite, but I think it will do erverything I want to do.

Offline DAlgie

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Re: CNC lathe
« Reply #15 on: May 18, 2007, 01:55:50 AM »
All sounds very nice! As a bit of caution, when you get a quick change tolpost and toolholders, be careful to take the time to learn how the lathe too offsets work on Mach3. It's not that straightforward at first and you can cause a crash if you're not sure how it's set up. A bit more complex than Mach3 mill I'd say, reply back here when you're ready and I can help if needed.
                                                    DaveA.
Re: CNC lathe
« Reply #16 on: May 18, 2007, 04:13:16 PM »
OK, Dave, thanks for the offer.  I will take you up on  it in a couple of days.  I just got a series 0 KDK tool post and 5 holders on ebay.  This morning I had to modify the top slide to take it, but everything worked out OK.   The nice thing about it is that the tool holders will fit the 100 KDK which I have on my big lathe, so I can just switch tool holders from one lathe to the other and just have to adjust the heigth.

Bob
Re: CNC lathe
« Reply #17 on: May 19, 2007, 04:30:41 PM »
Dave or someone, I do need some help.  I edited a program that I wrote and when I went back to auto, the display showed just a horizontal line.  After playing a little and enlarging I could see a tiny place with some red that I guess are the lines for the cuts made in the program.  It is so small it can berarly be seen. It looks like the scale on the screen is about 1/50 of the size it should be.  I can't find a way to get the size of the object large enough to see the individual cuts so I can watch he program run to see if it is working ok.   Any help would be appreciated.

Offline DAlgie

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Re: CNC lathe
« Reply #18 on: May 19, 2007, 06:03:22 PM »
Post the program on here and we can take a look at it. if you click on the graphic display partion of the screen you can then zoom in, use your scroll wheel on the mouse, and also pan the view if needed, try it and you'll see it's very nice to use. I use the "Silverblue" screenset available on here, same controls but a much nicer display.
Re: CNC lathe
« Reply #19 on: May 19, 2007, 10:32:32 PM »
Dave, it is not the program as I have run it several times before.  I also have two other programs that used to work and now do the same thing.  I know about clicking on the display and zooming in.  When I do this the horizonal line (which represents the cylinder to be turned) goes from a line to a cylinder of about 1/16 in diameter!  I tried another tack.  I had originally programed these programs on a laptop, so I copied the program on a USB memory stick and the put it into the lathe computer and loaded the program from it.  At first it showed the same horizontal line, but when I hit the regenerate toolpath button, voila, the screen showed the tool path full size.  Why?  I don't know.  I had tried the regenerate button on the program loaded from the lathe computer and nothing happened.

I guess I will just trash the programs on the lathe computer and reinstall them from the laptop.  I plan to always write the programs on the laptop so I have a fall back in case this happens again.  I am sure though that there must be a way to change the scale on the screen, but I can't find it.