. .

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    Quote Originally Posted by JAZZCNC View Post
    Ok well first, the ribs on the front plate add virtually nothing but weight because the plate is fastened directly to the bearings with no overhang, it's also short and strong so very little vibrations come from that area.

    Regards the plates on the sides then these would help, however, I have a better suggestion. If you look at the pic and at the other machines I've built I always put a cover over the Z-axis. This isn't just to protect from debris it's also structural as it does the same job those plates. You don't need a 10mm plate, I use 3mm for the covers and it's more than strong enough.

    The spindle mounting area is limited to the lower area (see the pic, it's the silver area, the black is drawbar cylinders.) However, they are steel and would easily handle another clamp.

    Regards putting the spacer plates on the front plate to save weight then I wouldn't do that either because of your shifting weight to the wrong area.
    To be honest I wouldn't use spacer plates as it lowers precision and makes it complicated.

    Regards Motor brake then I can't answer that because I don't know those motors, but servos are not like steppers where they have a shaft sticking out the back, mostly because this is often used for the encoder.

    How the motor handles the weight will depend on usage, but if you plan on doing 3D type work with lots of short moves with high acceleration then I think they 180W motors will struggle with the inertia and you'll get some following errors. Because again servos are unlike steppers where if they lose the position you visually see the lost steps, instead the encoders along with the drives close the loop and catch back up so will always return to exact same place when stopped provided they don't go outside of parameters set in the drives.

    However, what you get is a following error which if it stays within following error parameters can trick people into thinking they don't have a problem because if they do a type of work which is mostly 2D the Z-axis isn't whizzing up & down so it gets missed.
    Click image for larger version. 

Name:	z1.jpg 
Views:	4669 
Size:	867.6 KB 
ID:	27530 Click image for larger version. 

Name:	z2.jpg 
Views:	4677 
Size:	357.7 KB 
ID:	27531 Click image for larger version. 

Name:	z3.jpg 
Views:	4617 
Size:	648.6 KB 
ID:	27532
    JAZZ, I think the way you have installed the pneumatic actuators and the Z-axis cover design is great! The whole machine design is phenomenal.. I hope you don't me taking ideas and copying some features from it?

    I've removed my spacer plates now and added a machining to both the rear and the front plate to make room for the bearing and ball screw nut housing. This reduced the overhang by 15mm! It also reduced the total weight a few kg's. Thanks for the tip!
    Last edited by NordicCnc; 06-03-2020 at 10:38 PM.

  2. #2
    Quote Originally Posted by NordicCnc View Post
    JAZZ, I think the way you have installed the pneumatic actuators and the Z-axis cover design is great! The whole machine design is phenomenal.. I hope you don't me taking ideas and copying some features from it?
    No don't mind at all , go for it.! . . . Thou bare in mind some of these pictures are not of the finished article, the covers, for instance, are still missing some fastenings and slot covers, etc but hopefully show what I've been saying.

  3. #3
    Quote Originally Posted by JAZZCNC View Post
    No don't mind at all , go for it.! . . . Thou bare in mind some of these pictures are not of the finished article, the covers, for instance, are still missing some fastenings and slot covers, etc but hopefully show what I've been saying.
    Great and you have explained it very well!

    By the way I have now decided that I will not use the 180W JMC servo motors that I bought in advance. I've come to realize that they are holding me back by limiting the weight of he machine. It was an expensive learning lesson but now I know that I should always wait with buying any components until the design is completed.

    I've contacted the supplier and they might be willing to accept a return and I would pay a little more to get the 400W JMC servo motors in change (https://www.aliexpress.com/item/4000067490526.html). In case they don't accept the return for some reason then I have already found another use case for them, so that problem is solved - no money lost. If I then still buy the 400W JMC's, I don't know, I will have to check what you and the others here think. I saw that delta servo's were recommended as well and it was also mentioned that larger than 400W would probably be good?

    Anyway the motor power issue is now out of the way and I have the money to spend on new and way more powerful motors!

    So now having solved the motor power issue, do I still keep the Z-axis weight as low as possible or should I start trying to beef it up? The covers I will design to be structural, taking ideas from your machines JAZZ. The Z-axis front plate I am not so sure if I can improve much since it is already very stiff. Perhaps the Z-axis design is good as light weight and I can just stop worrying if the motor power will be enough to handle the heavy ATC spindle!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. BUILD LOG: New Build - For Your Amusement - MK-2 build
    By Karl in forum DIY Router Build Logs
    Replies: 12
    Last Post: 08-02-2017, 08:03 PM

Bookmarks

Posting Permissions

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