Re: [CAD_CAM_EDM_DRO] Z axis conversion

I've been visiting a lot of CNC machine sites, looking for a good one. I
ran across one that always powers the knee and they claim many thousands of
hours of service with no problems. You might want to consider here that you
probably won't need an anti backlash nut due to the weight of the knee,
saddle, and work pushing down on it.

Smoke
-----Original Message-----
From: Wally K <cnc4me@...>
To: CAD_CAM_EDM_DRO@egroups.com <CAD_CAM_EDM_DRO@egroups.com>
Date: Monday, November 27, 2000 11:48 AM
Subject: [CAD_CAM_EDM_DRO] Z axis conversion

>I tend to agree with your "intrinsically crappy situation" statment.
>I keep going around in circles trying to figure out how to power the
>Z axis. All methodes seem to be bad. People that have seen the
>front quill methode of conversion tell me that the attachment screw
>to the quill always comes loose. I would not mind modifing my J head
>if i could come up with a good solution. And i still wonder if
>moving the knee is a good idea or not, in terms of wear. And or
>replacing the acme knee screw with a ball screw.
>
>
>Wally K.
>
>
>
>
>Marcus & Eva wrote:
>> Hi Wally:
>> All of the commercial conversions I have seen, mount a small Z
>axis
>> ballscrew to the quill.
>> This is probably the least offensive way out of an intrinsically
>crappy
>> situation.
>> The basic physics you are up against, is that an extended quill
>flops around
>> in X and Y, because it is cantilevered out so far.
>> This makes heavy cutting impossible, and accuracy a hit or miss
>affair,
>> depending on how far out the quill happens to be sticking.
>> Connecting the Z axis servo to the quill downfeed mechanism adds a
>> horrendous and variable amount of backlash to the equation.
>> I can't guarantee it, but I'm pretty sure you will be disappointed
>if you go
>> to all the trouble to make the mount, and then find you can't
>machine
>> anything to closer than boilermaker's tolerances.
>>
>> Cheers
>>
>> Marcus
>> -----Original Message-----
>> From: Wally K <cnc4me@u...>
>> To: CAD_CAM_EDM_DRO@egroups.com <CAD_CAM_EDM_DRO@egroups.com>
>> Date: Monday, November 27, 2000 6:06 AM
>> Subject: [CAD_CAM_EDM_DRO] Re: wrong guy, but have servo question.
>>
>>
>> >Jon Elso wrote:
>> >
>> >> I used 200 Lbs force for the quill, as that is what the
>Bridgeport
>> >J-head's
>> >> overload clutch is set to on the power feed. I punched the wrong
>> >jog button
>> >> and brought a boring head down on my hand once, and it sure FELT
>> >like
>> >> 200+ Lbs!
>> >>
>> >> Jon
>> >
>> >
>> >Wally K. replys:
>> >
>> >Do you think the feed mechanism could be used for the Z axis on
>CNC.
>> >I think the little hand wheel on the side of the J head can be
>> >switched in to be manually turned to lower the quill. It would not
>> >be to hard to put a motor in place of the handwheel.
>> >
>> >Is this mechanism made for this kind of duty cycly.
>> >
>> >And how much backlash does it have.
>> >
>
>
>
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