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  1. #21
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    Default Re: Please help with machine chatter & movement

    If you want a reliable spindle for less look for a RECON unit, a recon from a decent spindle brand will outlast and outperform any brand new Chinese offering.

    5hp Italian Elte air cooled spindle run 5 days a week for over a decade with no worries- purchase cost as a recon was less than a grand (12month warranty). After a decade the thing wore out so we sent it back to Italy where Elte did a complete factory rebuild for 400 euro. This is CHEAP routing by any measure.

    As far as VFD's go I'd recommend Taiwanese CUTES brand equipment.... we got 13 years reliable service before a refurb was required, cost for the refurb was less than 50% of the price for a new unit.

    Air cooling isn't an issue if your spindle is properly engineered and carefully balanced during assembly- small hp Chinese spindles need water cooling... large hp European spindles don't. The difference between the two is simply quality.



  2. #22
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    Default Re: Please help with machine chatter & movement

    Gary,

    Looking at the design of the machine with the new photos, I see a LOT of areas where the machine is not very rigid. This lack of rigidity is where you will get chatter.

    1) As pointed out previously, the router mount is very weak, could be beefed up with gussets to join the horizontal and vertical parts.
    2) long, un-supported round shafts (bearings appear to wrap all the way around the shafts). There is very little rigidity in these rails, introduce cutting vibrations and you got a "chatter box"
    3) Poorly supported table. There is very little structure supporting the table and thus the part. I bet with very little pressure pushing down on that table, you can get it to deflect .010" to .020" easily.

    Is the machine "junk", I don't think so. Can it work and do what you want, probably. Like any machine, you have to work within it's capabilities. In your case, lighter cuts, lower feed rates, and probably different cutters, for example; cutters with a helix flute as opposed to straight.

    Chris D



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    Default Re: Please help with machine chatter & movement

    Chris, I just reread you post and like I said I'm new to CNC so my terminology is probably wrong but you mentioned long unsupported round rails... the rails are supported to the aluminum frame at every mounting point (I'd say ever 10" or so) and the bearing go probably 3/4 the way around. Trust me I'm not defending the machine & I understand the round rails aren't the way to go anymore. I'm just trying to make sure you understand what I'm working with.

    Is it going to be possible for me to change out the linear rails to profile linear rails?

    What size ( width ) of linear rails should I use on a 4'x8x router?

    I'm torn on my initial upgrade, what would I receive the best return on?
    Upgrading the router to a Spindle & VFD or changing out the linear rails and adding support to the router bracket?

    Thanks for the help



  4. #24
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    Default Re: Please help with machine chatter & movement

    Unless the router is under powered and bogging down, you probably won't notice much of a difference by going to a spindle.
    #1, is to stiffen up that router mount.

    What you are looking for is rigidity. The machine needs to be as rigid as possible.
    Is it going to be possible for me to change out the linear rails to profile linear rails?
    I don't know. You can easily find the sizes of the rails and bearing blocks, and see what you'd need to do to make them fit?

    Linear rails would probably make the biggest difference, but are the most expensive option. And you may find after you install them, that your frame isn't all that rigid. If you decide to go that route, you'd probably want 20mm, unless 25mm is a better fit.
    15mm rails are probably 10x better than what you have, but they are very small, and hard to work with. 20mm rails are only a little more expensive, but are much easier to work with.

    Is the machine rack and pinion? Is there any slop between the pinion and rack? If there is, you'd want to address this first.

    Gerry

    UCCNC 2017 Screenset
    [URL]http://www.thecncwoodworker.com/2017.html[/URL]

    Mach3 2010 Screenset
    [URL]http://www.thecncwoodworker.com/2010.html[/URL]

    JointCAM - CNC Dovetails & Box Joints
    [URL]http://www.g-forcecnc.com/jointcam.html[/URL]

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)


  5. #25
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    Default Re: Please help with machine chatter & movement

    Gerry, no the router isn't bogging I wanted to switch to the Spindle to get the weight off of the router bracket.

    How do I find what size rails I need?

    Yes it is a rack and pinion for X & Y and ball screw for the Z.
    It doesn't feel like it has play in the movement.

    Thanks



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    Default Re: Please help with machine chatter & movement

    Gary, start with the simple things first. Make sure everything is tight, base frame needs to be rigid. Next, check each axis for excessive movement there shouldn't be any side-to-side or up and down movement. If you get movement on any of the axis correct it or replace the bad component.

    I'm not familiar with your router and if it is a constant speed model, 30 in/min is to slow. This is where 'speed and feeds' come into play and there are many calculators available on the internet. What all of this means is that there is a direct relationship between the cutter (number of cutting edges), how fast it's rotating and how quickly it's moving thru the material. What you want to do is target what is known as Chip Load.



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    Default Re: Please help with machine chatter & movement

    PLCLAMP - like if said I'm new to CNC, so how can I tell if it is a constant speed machine? And you say 30 in/min is to slow & others have said shallower cuts and slower speeds, what speed should I cut at?

    If anyone is near North western Pennsylvania (Clarion County) and would be willing to give me an idea of what needs updated & in what order to do the upgrades I would greatly appreciate the help.

    Thanks



  8. #28
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    Default Re: Please help with machine chatter & movement

    what speed should I cut at?
    That depends on what you're doing. It could range from 30ipm, to 300ipm.

    For maximum tool life, you want to cut as fast as possible, with the lowest possible RPM. If you want the highest quality, it'll probably require slower cuts and/or higher rpm. Spindle power and machine rigidity has a big effect on cutting speeds.
    Bottom line, there's no one answer, as different machines have different capabilities, and different projects also have different requirements.

    Gerry

    UCCNC 2017 Screenset
    [URL]http://www.thecncwoodworker.com/2017.html[/URL]

    Mach3 2010 Screenset
    [URL]http://www.thecncwoodworker.com/2010.html[/URL]

    JointCAM - CNC Dovetails & Box Joints
    [URL]http://www.g-forcecnc.com/jointcam.html[/URL]

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)


  9. #29
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    Default Re: Please help with machine chatter & movement

    Garry,

    As Gerry pointed out, there is no single answer to your question. The speed you select is in this case, I beleive controlled by the fixed RPM of your router. If it is a variable speed router, start in the middle - it is as good a place as any.

    The feedrate you have total control over, you program it it to what you want. Start out at 10 IPM and make a cut, then if that is okay try 20 IPM, and so on until the cutting conditions sound good and the cuts look good.

    The next variables that you have a lot of control over are the cutter diameter and the cut depth.

    Simple rule, try not to cut deeper than the diameter of the cutter - example, 1/2" router bit - try to stay under a 1/2" depth of cut.

    You don't need to take all cuts at full depth. You may need to take two passes for a cut, for example 1 and 1/4" depth and the next at 1/2" depth.

    You may be trying to cut with a 1/2" diameter cutter, perhaps 1/4" diameter works better.

    This is all part of the learning curve and only you can go through the experiences with your machine.

    Gerry's machine(s) are most certainly different than my machines - neither of us would use the exact same speed, feed, cutter size, cut depth etc. We would try a few conditions and go with it if it sounds good and produces the required results.

    Industrial CNC machines cutting metal are in practicality no different. Luckily, there are published recomendations for speeds and feeds that should work if the machine is rigid, the spindle has enough power, etc..

    I highly recommend getting some cutting time with your machine. Cut along the X axis, Cut along the Y axis, try it with different speeds, feeds, cutters, depths of cuts and learn from all of that. Try to cut different materials: MDF, Particle board, Pine, Hardwoods, Plywoods, etc. Most wood products behave pretty similar but there are differences. While doing all this cutting, observe your machine, put your hands on it, feel the vibrations, look for areas that have a lot of vibration and see if there is a way to siffen it up.

    It is a lot to learn and a lot to explore, but, in my opinion, that's why many of us actually do the "DIY CNC" thing.

    Chris D



  10. #30
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    Default Re: Please help with machine chatter & movement

    Thanks for the replies, I'm waiting on the aluminum support to be made so I can get the router bracket tightened up, then I'm going to use it as Chris & Gerry mentioned I'm going to use it & learn then either upgrade my system or purchase another machine.

    Once I get my supports finished I'll post some photos

    Thanks again



  11. #31
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    Default Re: Please help with machine chatter & movement

    Ok so I was able to get the braces on and I've played around with the router a little this week. I believe the braces helped a bit but I still have some chatter, in my opinion it's from the linear rails mainly the X seem to be a little worse than the Y. I slowed down the feed rate and I'm getting very acceptable results but it is SLLLOOWWW and I'm not sure if it will be cost prohibitive to charge by the hour. What is the min. Speed (in / min) that is fast enough to be worth running. I definately want to rebuild the router or at the very least replace the linear rails as soon as I can make some money with this machine. Here is the bracket that I put on the router bracket. Let me know your thoughts.
    [ATTACH=CONFIG]371858[/Please help with machine chatter & movement-20170831_172941-jpg]
    Thanks
    Gary



  12. #32
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    Default Re: Please help with machine chatter & movement

    Speed (in / min) that is fast enough to be worth running
    It depends what you're doing, but probably 200-300ipm. But even if it can go that fast, or faster, the machine rigidity and spindle power will dictate how deep you can cut.

    Gerry

    UCCNC 2017 Screenset
    [URL]http://www.thecncwoodworker.com/2017.html[/URL]

    Mach3 2010 Screenset
    [URL]http://www.thecncwoodworker.com/2010.html[/URL]

    JointCAM - CNC Dovetails & Box Joints
    [URL]http://www.g-forcecnc.com/jointcam.html[/URL]

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)


  13. #33
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    Default Re: Please help with machine chatter & movement

    Ugh i really need an upgrade / rebuild i was routing at 25 ipm to to get good smooth cuts. I tried 100 chattering bad then 50ipm with ok results but still a little movement.

    What maintenance should I do to the rack & pinion or guide rails? I asked the original owner & he said " we didn't do anything "which seemed odd to me that You would run the rails dry. The rack has some grease on it. Every time I reach in there I get grease on my hands

    Thanks



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    Default Re: Please help with machine chatter & movement

    Are the pinions sring loaded into the rack at all? If not, that could be a source of your issues. Anywhere that there
    s any play or backlash in the machine will cause issues.

    Gerry

    UCCNC 2017 Screenset
    [URL]http://www.thecncwoodworker.com/2017.html[/URL]

    Mach3 2010 Screenset
    [URL]http://www.thecncwoodworker.com/2010.html[/URL]

    JointCAM - CNC Dovetails & Box Joints
    [URL]http://www.g-forcecnc.com/jointcam.html[/URL]

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)


  15. #35
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    Default Re: Please help with machine chatter & movement

    I'm not sure what sring loaded is.



  16. #36
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    Default Re: Please help with machine chatter & movement

    spring loaded.

    Gerry

    UCCNC 2017 Screenset
    [URL]http://www.thecncwoodworker.com/2017.html[/URL]

    Mach3 2010 Screenset
    [URL]http://www.thecncwoodworker.com/2010.html[/URL]

    JointCAM - CNC Dovetails & Box Joints
    [URL]http://www.g-forcecnc.com/jointcam.html[/URL]

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)


  17. #37
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    Default Re: Please help with machine chatter & movement

    Gary,

    For what it is worth....

    Industrial CNC Machining Centers (big machines that cut metal to very close tolerances) also cannot put a perfect finish on a part at a fast feedrate. Finishing is often done at a lighter depth of cut and a slower feedrate so that the finish and precision can be achieved - it is the way of machining and it is universal.

    In your case, you are fighting a number of issues - I suspect a lack of rigidity and probably some slop (play) in the various components. If you had the opportunity to cut on all the DIY CNC routers out there, I would bet more than 80% of them can't do what you want at the speed you want. Designing and building a tight and rigid machine is difficult at best and next to impossible for most hobbiests.

    Chris D



  18. #38
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    Default Re: Please help with machine chatter & movement

    Gerry - As you know I'm new to CNC where would the spring be located? I haven't seen any obvious springs but I'm 6'7" 310# so getting in under the router isn't the easiest for me but I can look again.

    Chris - thanks I have a friend that owns the areas largest machine / fab shop and he was telling me the machine aluminum at 48 imp I did forget to ask him how deep of passes he makes but I was shocked at how slow he was routing, after hearing the speed being talked about on here. I'm using V-carve Pro is there a way to set the finish path at a slower speed than the regular cutting / routing?



  19. #39
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    Default Re: Please help with machine chatter & movement

    Fwiw, we cut cabinet parts at 1200ipm, but it's a $150,000 machine. I rough cut hardwoods at 300-400ipm, and do a finish pass at 150-200ipm.
    You can finish cut at high speeds, but you need a powerful and rigid machine to get good results.

    In V Carve Pro, when you are creating the toolpaths, click the Edit Tool button, and you can set the feedrate and rpm there. Each toolpath can have it's own feedrate and rpm.

    Can you post some pictures of where the pinion engages the rack?

    Gerry

    UCCNC 2017 Screenset
    [URL]http://www.thecncwoodworker.com/2017.html[/URL]

    Mach3 2010 Screenset
    [URL]http://www.thecncwoodworker.com/2010.html[/URL]

    JointCAM - CNC Dovetails & Box Joints
    [URL]http://www.g-forcecnc.com/jointcam.html[/URL]

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)


  20. #40
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    Default Re: Please help with machine chatter & movement

    Please help with machine chatter & movement-20170903_171651-jpgPlease help with machine chatter & movement-20170903_172045-jpg
    Gerry, here are the photos of where the pinion meets the rack. If you see anything with this design let me know. The X-axis is hard to get a good photo of, but the photo of the Y-axis is much easier to get a shot of.

    Thanks



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