584,849 active members*
4,538 visitors online*
Register for free
Login
IndustryArena Forum > MetalWorking Machines > Mori Seiki Machines > Mori Seiki lathes > Drilling and Roughing/Finishing simultaneously
Results 1 to 8 of 8
  1. #1
    Join Date
    Mar 2012
    Posts
    0

    Drilling and Roughing/Finishing simultaneously

    Mori Seiki ZL-200
    Material: 1.141" DIA BAR 52100
    Drill Bit: #20 size parabolic carbide TiAlN coated
    Roughing Insert: DNMX-442 Carbide
    Finishing Insert: VNMG-331 Cermet

    We are trying to optimize production by keeping both turrets active during the entire production process. The only way to do this on some of the cam followers we produce is to have the thru hole drilled on the part on the main spindle while roughing/finishing with the other turret. Usually we split the turrets up to work on the main and sub spindle separately, but all the operations available on the sub spindle are taken care of.

    I got some carbide drills that can handle the rpm's used while roughing/finishing which seemed to be the only issue besides making sure both turrets have adequate room to work without crashing into each other, but I just wanted to get a second opinion on this. Will one operation affect the other?

  2. #2
    Join Date
    Aug 2011
    Posts
    2517
    I programmed and operated ZL's for many years.
    there are a few issues.

    the main one is the speed difference between both tools if they are cutting at different diameters.
    use G97 and set a speed in the middle, or good for one tool which will be slower or faster for the other.
    if you use G96 the lower turret has priority but beware if the upper turret is cutting and the lower turret finishes and starts to rapid back for the next tool change the spindle will slow since lower turret has priority in G96. so the upper turret will cut *very* slowly from there until the lower turret comes back in on the next tool.

    another thing to watch out is forces on the part. because there is no tailstock you have to be careful when taking your roughing cuts that the job does not move because 2 tools puts twice as much force on the part.

    another thing to watch is when roughing and finishing together it tends to leave a small mark on the job when the roughing tool starts and ends it's cut or rapids in and out. it could have just been our machines were not leveled properly or bolted down properly but we ended up having to put in a wait (M100 and upwards) to stop one turret until the other tool had finished otherwise we got a small line on the job. it wasn't a step, just a line that was visible.

    of course twin turret interference is always an issue so always look for that. any collision can be avoided by simply making one turret wait a few seconds until the other turret is out of the way (again M100 and upwards for waiting codes on both turrets). the easiest way to check it is run each turret separately and cut the metal.
    then run both turrets together (single block must be off so waiting codes are read and buffered correctly) and turn the coolant off as well. your rapid can be low it doesn't affect the tool positions because if its programmed correctly the waiting codes will ensure the turret waits for the right time to continue. with no metal cutting and coolant off you can concentrate more on watching the tools and that they are synced correctly.

  3. #3
    Join Date
    Jun 2005
    Posts
    142
    You would be surprised what you can get away with, speed/feed wise.
    I used to machine cast disc rotors using a 30mm u-drill while turning od (280mm) and facing (280mm-105mm).
    Most attention is needed in choosing what grade your inserts will be.
    Have fun,
    Dave.

  4. #4
    Join Date
    Mar 2012
    Posts
    0
    Thanks guys, I finally got my carbide drill in and will be testing the program today and will post the results.

    So we ran the parts yesterday and the drill broke last night after about 130 parts. Not cost effective at all at about $1/part for the cost of the drill.

    The roughing is set to G50S3800 G96S650 so the revolutions range from 2000 to 3800. I gave the drill a feedrate of .0028 IPR. I was thinking of setting a constant RPM on the roughing instead of constant SFM. But I think my main issue is the RPM are pretty low for the drill, which is calling for RPMs above my machine max of 4000. I could really use some help with this. My cobalt #20 drills were lasting for more than 500 parts and they are dirt cheap. I may just have to settle for the higher cycle times...

  5. #5
    Join Date
    Aug 2011
    Posts
    2517
    when using twin turrets it's always better to use fixed RPM. An automatically generated program written with FAPT on 15TTF etc uses RPM not G96.

  6. #6
    Join Date
    Jun 2005
    Posts
    142
    Bummer.
    If this is a new drill that you haven't much experience with, I would suggest running it simply as a replacement for your cobalts, using your original process (with correct cutting data for the new drill of course) to prove to yourself it's a good drill and will last.
    Once your satisfied, you can try and crank both turrets simultaneously.

  7. #7
    Join Date
    Mar 2012
    Posts
    0
    That's a good point. I have 3 more on the way since the company was changing suppliers and could only provide the one at the time. I'll do that once they come in. Thanks.

  8. #8
    Join Date
    Mar 2012
    Posts
    0
    Still waiting on those bits...they're supposed to ship next week.

    I took out that broken carbide bit the other day and saw some things I didn't notice in my frustration when it broke. First, its sharp, and the coating isn't worn. Second, there is a small chip off the tip, at the end of where the point slopes down to the OD. Third, the fracture seems to indicate that the drill broke from a force perpendicular to the axis. I believe it was touching the work piece at the tip and the turret moved in the x direction, causing the chip and the fracture pattern. How this happened, I have no idea, but at least I know it wasn't the drill bit's fault.

Similar Threads

  1. Roughing and Finishing in One Profile
    By nfrees114 in forum BobCad-Cam
    Replies: 13
    Last Post: 10-07-2009, 11:33 AM
  2. 3D Milling (Roughing & Finishing)
    By mattpatt in forum SolidCAM for SolidWorks and SolidCAM for Inventor
    Replies: 21
    Last Post: 01-11-2009, 10:00 PM
  3. roughing/finishing technique
    By fpworks in forum Hard / High Speed Machining
    Replies: 14
    Last Post: 10-14-2007, 05:33 PM
  4. There's no Roughing/finishing option?!?!
    By ajinjax in forum BobCad-Cam
    Replies: 5
    Last Post: 10-05-2007, 01:16 PM
  5. Roughing/Finishing???
    By trevorhinze in forum BobCad-Cam
    Replies: 1
    Last Post: 08-02-2005, 11:14 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •