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As built

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This photo was taken June 2013 soon after completion, although it is still missing one cover plate. I have been running heavily since I really have no regrets on this project. the following photo album was kept up as the build took place. I have been continually impressed with the mach 3 control system which really seems to be an industrial quality controller.

 


Controls and Bench test

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  -Project Started 1/12/13-

So in the process of making my DD40, the amount of parts needed in the trucks is overwhelming, it takes a long time to make a truck set when you can only work on it 2 days a week. I  sold the first DD-40 set that I made, and had interest in a few more. This presents a chalange in that I am barely able to meet my personal production demand. The answer ....CNC.

Recently my father and I had toyed with the idea of a CNC router and both came to the conclusion that it would be fun, but did not fill a need that could justify the cost.  Now it does, so here we go. I have already selected the lathe I want but before I jump off the bridge I want to make sure that the control system is feasible. I have ordered the stepper motors, and drives, an interface board and a few parts needed to bring this $30 Dell up to speed to control it all. I will use Artsoft's Mach 3 CAM software, the trial is a free download to start. 

      I think that the time spent building the CNC will make up for itself quicly once I get it running, I should be able to do a weekends worth of parts in an afternoon. I have alot of big projects coming up and production will be the key to all of them and that is currently the wek point of my operation. I looked at farming the work out to a machine shop but the price was just too high.  So here we go.

 

 

 

 

 


Wow, Its easy...

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   The bench test was a total success. The system was configured and running in an hour. I really wonder why everyone doesn't have one.

   Here's the video of the bench test http://www.youtube.com/watch?v=NrLRE4agUZw

   At this point I had already done 2 electronics upgrades, I figured this would happen, First I was kinda dissappointed with the motors, I origionally figured on a smaller lathe and even though I oversized the motors, it wouldn't have been enough. I also did not like how easily the steppers positioning can be lost if they stall. I opted for a hybrid servo, a stepper motor with a closed loop control to prevent loss of sync. they work incredible. Next I found that I could not have the resolution and speed I wanted, either one I could do, just not at the same time. The issue is a windows problem, Mach 3 being on the windows platform has to share system time with windows and this becomes when producing pulsetrain commands, you wind up with your steppers being jumpy and stalling easily, and overall just unpleasant. The only solution I see is the smooth stepper motion controller so that will wind up on the machine before the first run.

 

 

 

 


Green Eggs and Lathes?

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  Immediatley after proving the control system, it was time for the machine itself. I have had great luck with Grizzly Machines so I decided on their G4002 Lathe, a 12"x24" machine with 2Hp. The 36" bed was only a few $ more but I don't think I have ever used more than 18" of the 40" lathe I currently have, so I saved space.

    So you can see in the photo, I have already removed the manual components, and other parts no longer needed. The motor for example will be swapped out with a 3ph motor run from vfd. other things like the compound feed, threading gears, etc, are just not necessary on a CNC machine. Out with the old build the new.

 

 

 

 


Phasers to stun

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  To get spindle speed control I had to switch the motor to 3 phase power so that I could run it with a VFD. I wish Grizzly offered a 3Ph option but they don’t.  It has an IEC motor which limits your options to basically one choice, a Leeson 192205 @ $240, more than I wanted to pay but it is a very good motor.  A 184T motor is close but, I think when considering the rest of the items needed to change it and the time, it would have been a wash.  It is a D90L frame size in case you are wondering.

 

 


As promised

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  I have been Making great progress on the Lathe in the past couple weeks, of coarse doing that means I have not done well keeping up with the website... Anyway today should be a big day I should have both axis and the spindle under Mach 3 control and the toolpost is muonted. I will resist the temptation to make chips until I get the cover made for the Z ballscrew . The picture is the z axis drive mounted and hooked up.

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Mini project....really?

Lathe Ballnut 2.jpg

 

 

  In one of my other threads you read about "Mini-Projects" well this is a perfect example. Ballnuts are a ball bearing version of a regular nut and the come in a variety of types one type being "zero-lash" or "preloaded" that is the type you would want for this application because....obvious. With the preloaded nuts being wildly expensive I spent a little while looking for a cheap solution and since I am such a resourcefull fellow I found the answer on one of the CNC forums. Using a pair of $25 ballnuts from Roton I made a threaded spacer to adjust the preload and mounted them together on a plate that keeps them aligned. Perfect. So, back to my point, this is a beautiful part a great piece in its own that will be hidden out of sight and un appreciated.

 

  


Compounding problems

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     Sure don't need a compound feed on a CNC Lathe....

 I removed the compound slide and replaced it with a rigid post, this should eliminate any deflection that would have been caused by the slide or nut. I think it came out nice.

 


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