Re: Ideas for matching drives on a YY axis design?
Posted by
dakota8833
on 2002-10-22 19:28:49 UTC
--- In CAD_CAM_EDM_DRO@y..., "Doug Harrison" <prototype@c...> wrote:
this and noticed that it was more efective to drive it down the sides
or single down the middle. What one has to keep in mind is the lever
action. Driving down the center halves these forces as opposed to a
single drive at one side. Looking from under the table the structure
would look like bowtie,.. two triangles |><|,.. great stiffness.
Additional stiffness in the X axis run would come from rail
"overbuild" and with the table top asmy. Another problem with single
sided drive is with the twisting of the ganty uprights. It is doubled
for the same size mill. Any of these problems can be overcome though
,..by overbuilding. I like unconventional thinking and may use the
same concept with my next mill. I would like to hear some more about
your idea of a single sided drive.
Frank ,.... CAD CAM FEA backround
> I have seen quite a few gantry drives with one screw down the centerunder
> the table. This presents two problems. First, the table must besupported
> at the corners which limits stiffness. Second, the moment loadsdeveloped
> when the head is at either end of the gantry cause wracking of thegantry
> (and deflection of the limp table caused by the first problem).table and
>
> The usual solution to these problems seems to be overbuilding the
> gantry. Neither work very well. A more effective solution is todesign the
> gantry so it can be driven from one side. This works surprisinglywell,
> though it requires some unconventional thinking to accept. I wouldchoose
> this approach if I were doing it again.belts to
>
> Another approach is to use two screws and link them together with
> the motor, which will then have two pulleys. The motor is placed atone end
> of the table between the screws. Any loss of accuracy from the longbelts
> will be insignificant compared to Abbe errors, thread drunkennessand
> thermal stratification in a sub$80K machine.Funny you should mention driving the ganty from one side ,.. I tried
>
> Doug
this and noticed that it was more efective to drive it down the sides
or single down the middle. What one has to keep in mind is the lever
action. Driving down the center halves these forces as opposed to a
single drive at one side. Looking from under the table the structure
would look like bowtie,.. two triangles |><|,.. great stiffness.
Additional stiffness in the X axis run would come from rail
"overbuild" and with the table top asmy. Another problem with single
sided drive is with the twisting of the ganty uprights. It is doubled
for the same size mill. Any of these problems can be overcome though
,..by overbuilding. I like unconventional thinking and may use the
same concept with my next mill. I would like to hear some more about
your idea of a single sided drive.
Frank ,.... CAD CAM FEA backround
>so it
>
>
> ----- Original Message -----
> From: Jim Brown <jagco1998@y...>
> >
> > Just curious............
> > Why cant you just space out the linear bearings on the z/y axis'
> will have less of a chance of binding when traversing in the x axis,and
> drive it from the center with the ballscrew/leadscrew?of the
> > I realize that this will be a big feat to perform, being the width
> gantry. But It can be done, cant it?
Discussion Thread
caudlet
2002-10-22 10:44:45 UTC
Ideas for matching drives on a YY axis design?
deanc500
2002-10-22 11:02:53 UTC
Re: Ideas for matching drives on a YY axis design?
Jim Brown
2002-10-22 13:58:29 UTC
Re: [CAD_CAM_EDM_DRO] Ideas for matching drives on a YY axis design?
Doug Harrison
2002-10-22 17:28:00 UTC
Re: [CAD_CAM_EDM_DRO] Ideas for matching drives on a YY axis design?
dakota8833
2002-10-22 19:28:49 UTC
Re: Ideas for matching drives on a YY axis design?
Gene
2002-10-23 00:05:09 UTC
Re: [CAD_CAM_EDM_DRO] Re: Ideas for matching drives on a YY axis design?
caudlet
2002-10-23 05:06:12 UTC
Re: Ideas for matching drives on a YY axis design?
turbulatordude
2002-10-23 08:23:06 UTC
25Khz glitch ? (was Re: Ideas for matching drives on a YY axis design?
deanc500
2002-10-23 17:23:38 UTC
25Khz glitch ? (was Re: Ideas for matching drives on a YY axis design?
JJ
2002-10-24 05:35:58 UTC
RE: [CAD_CAM_EDM_DRO] Re: Ideas for matching drives on a YY axis design?