Newfangled has just got there second CNC lathe  It is a Compact 5 made by Emco and will be used to test software. The cost of the lathe was $900.00 and is in running condition! When I say running I should say that it needs spindle bearings… I turned on the spindle and it sounded like some one had put rocks in place of the bearings! So you will see that I have the spindle out of the lathe and the new 6006-2Z bearings are going to be on there way soon. I can only find ABEC 3 bearings from MSC ( www.mscdirect.com ) so I am going to call a few of the local bearing places to see if I can get ABEC 7 bearings . The ABEC number is the precision of the bearing, so a 7 is better than a 3… We could get into it more but I don’t see the point . Even with the bad bearings the lathe gave a GREAT finish! I was taking about .050 at 2500 RPM in 6061 AL with the stock about 2 inches out from the chuck. So there is hope for this little lathe



Now that I know everything is in working order I have to figure out what I am going to keep and what is going to go. The spindle motor is a German DC permanent magnet motor (very nice motor). The Emco DC spindle drive has a pot, LED display and a switch to turn it on and off. This will never do! I need to have CSS and don’t want to turn on the spindle motor on and off with a switch. I was going to get a KB electronics DC drive but there were not any dealers up here in Maine . So after looking on the web I found www.e-motorsonline.com and ordered a regenerative SCR DC drive. I was going to get a nonregenerative drive because they are half the money but this drive would not reverse and decelerate as fast as I would like . I ended up with a Minarik DCD01330 drive that is made to only run permanent magnet motors to the tune of about $183.00 with shipping.


I need to send a 0 – 10V to run the drive… I decided to order a DL06 PLC from automation direct with an analog card. I know this is WAY overkill but I know I will have all the IO that I will ever need . It  cost about $300.00 and gives 20 inputs, 16 outputs, 2 analog in and 2 analog out! The extra I/O is going to be used on the tool changer.. The way Emco did there tool changer is VERY odd at best! Emco did the tool change based on time! They never knew where the tool was at any point and a tool change would only tell it to increment X amount of tools! This will never do! I plan to add proximity sensors to the tool changer so Mach 3 will know what tool is tool one and to sense when a tool has gone by (counter). This will be a great improvement over the OEM convention of running the tool changer!


There are steppers on the X and Z axis… I heard that the steppers were junk so I did a few testes to see if I could get the machine to miss steps. The first one was to hold onto the tool changer and have a friend rapid the Z axis. I am not a small guy so I figured I could stop the axis if the steppers were not any good . I am happy to say that the machine started to slide across the plywood bench as I was holding the changer! The drives that are on it now are running heavy amps (about 4) so they are getting hot! I am in hopes that the new G201 drives from Gecko will help keep the motor cool with the auto current reduction. I plan to use the OEM transformer (40 V) , rectifier and capacitor.

For breakout board I went with the PMDX-122 and PMDX-Sensor-S from   www.PMDX.com  . I had the PMDX-122 sitting here because I bought it from Steve at the CNC workshop . The PMDX-Sensor-S is a through beam type sensor that I am going to use to read the spindle/position for threading. This is going to make for a nice small package that should all fit in to the original cabinet. 

That is all I have done up to this point  I will post more when the parts start to come in.

Feel free to ask any questions that you like
Thanks
Brian

Brian..   The steppers on these machines are 7.2 deg not the normal 1.8 deg.  It is worth changing then for some better more modern motors.

I run two of these machines commercially for very small parts.  Mainly in Acetal.   One machine is very standard with the toolchanger (Which I never use cos it's sooo slow)  The other is so heavily modified it could hardly be the same machine.

The modified one has a new 3/4" capactity spindle, with Angular contact bearings instead of those crappy deep groove bearings.  This spindle has a large chuck mount, which is made to suit the air operated collet chuck i am developing.  The dc spindle motor has been removed and turned into a dc servo for another machine!   All remaining holes in the base have been welded up cos I use flood coolant.    Removing that Loooong dc motor and replacing it with a 3/4hp 3 phase motor fitted in the rear we the psu used to live gave me room for a longer crosslide and ballscrew which turned to machine into a gang tooled machine.

I can run this spindle to 4500 rpm no problem and still be within spec of the bearings I have used.

But do bear in mind the headstock is a very light alloy diecasting! they dont take too kindly to much abuse....

Oneday I'll find time to finish it off!  I want to completely enclose it oneday.   If I get some time I'll post some pics somewhere.

Wayne....

I was going to test the motors first... What did you end up putting on for Axis motors? I will not be doing any high volume work on this lathe because I have a Hitachi Seki that is a MUCH better production lathe with a 12 station tool changer and 20 Hp 4000 RPM spindle.

Thanks
Brian

Hi,

Very intersting Brian. I'm currently doing a EMCO toolchanger module for the ModIO. It is my understanding that the toolchanger has to opto sensor it it. One for the home position and another for the tool position.

Every time a tool position is passed, the single tool position sensor is activated. It is also my understanding that  there is a Motor Forward relay that when activated drives the changer in the forward direction. When deactivated, the motor is constantly driven in reverse to lock the changer in position.

It is my understanding that it operates as follows;

The home sensor tells you it is locked in tool position 1. So, initially if you don't know where the current changer position is the changer needs to be rotated until the home sensor is detected, then keep going until the tool position sensor is detected. Then turn off the Motor relay and the motor will reverse locking the changer into tool  position 1.

We now know where we are. To select a tool position, the motor is enabled and the number of position sensor transitions are counted until the desired tool position is reached. The motor relay is de-energised and the changer reverses to lock it down.

BTW this changer has 6 positions though. Maybe it operates differently.


Also, I'm using the same ModIO register interface as I did with the Mazak tool changer. Maybe we should consider using it as a standard for tool changer modules as they all need the same type of control.

John Prentice wrote the MacroPump routine for it and it has been uploaded publically somewhere.

Cheers,

Peter.

Thanks for starting this thread Brian, it should be an interesting project. I look forward to reading all the details and seeing more pictures as you progress.

I have two of these machines one is in the original condition and the latest one has been retrofitted to use Mach3 by the previous owner. What I am interested in knowing is has anyone modified the Gib strip I understand it to be made of plastic.
Jim

What I am interested in knowing is has anyone modified the Gib strip I understand it to be made of plastic.
Jim

Yes I have modified them after a crash cracked the originals.   This caused the carriage to rock,   I machined up some new ones using some low friction plastic I had in stock (I forget what material it was, but it's green)   I made steel backing plates, which has made the assembly stiffer,  But you have to counterbore for the cap screws as there's not a lot of room before the screw heads foul on the beds crossbracing.

removing and refitting the screws can be difficult.  I drilled 2 holes in the pan to allow me to do this from under the machine.


Wayne...

Hello Peter,
This one has no sensors on the tool changer I was shocked! an open loop tool changer is just a little scary 

Could you tell me where your optics are on you changer?

thanks
Brian

Hello Brian,

I will go down to my shop and take some pictures of the toolchanger I have on my Emco PC Turn 50. It is the same one as you have with the encoder disk fitted.
You have the schematics and a small picture of the optoboard that I sent you earlier.

I'll be back
Bengt

Hi Brian,

Look at the new pictures of the optodisk setup on my Emco tool turret.

http://goto.glocalnet.net/Bengt.CNC.pages5/pictures.htm

Cheers
Bengt