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4 point bed support a mod too far?

Posted by Mickyblueeyes 
4 point bed support a mod too far?
February 10, 2014 07:46AM
Hi I have been trying to make the bed as solid and repeatable as possible so I can basically calibrate and forget it, in the process I decided to fix the bed to 4 linear bearings on an aluminium plate, while looking at this I also decided that the distance between the bottom rails leaves the bed overhanging contributing to the floppy nature of the construction so I have increased the distance from 80mm to 150mm giving a solid support for the bed.

To fix the bearing supports such that they wouldn't be affected by build tolerances and temperature effects the bearings are connected to the aluminium plate by short lengths of FR4 fibreglass acting as springs this is held between 2 printed parts such that approx. 14mm of the length is allowed to flex.

the undercarriage has been redesigned to incorporate a printed section on which a ternsioner and clamps connect the drive belt, the clamps are based on an offset cam action such that they self tighten as the belt is tensioned, its a little crude and not well finished but it proves a point.

Yes I know some of you wont like it but it works!.

if anyone is interested I will post the details here when I have tidied the design.



Edited 1 time(s). Last edit at 02/10/2014 07:46AM by Mickyblueeyes.

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Re: 4 point bed support a mod too far?
February 10, 2014 10:34AM
Nice work! - I especially like the aluminum supported y-axis-end-plates, this is one of the weak links of the original build, so no more setbed.g for you I guess?

Yes you may have gone a bit too far as you don't get the full return on the stability of the 4 bearing support with the springs added, but there is no such thing as over engineering! - very well done, and many nice details, thank you for sharing!

Re: 4 point bed support a mod too far?
February 10, 2014 11:28AM
Nice work!

You are running out of filament winking smiley


XBee & electronics blog: [lookmanowire.blogspot.com]
Re: 4 point bed support a mod too far?
February 19, 2014 12:29PM
Look very tough, btw. One concern about the mass on Y axis will be a bit too much?
This may reduce the max speed on moving. The building platform and more tension
On the belt when it need to stop due to larger momentum on the Y axis.
Re: 4 point bed support a mod too far?
February 19, 2014 12:40PM
Hi Chaisaeng,

It is heavier than before but so far it has performed perfectly and is a breeze to use, when I plan to increase the speed I will simply have to limit the rate of change to keep the forces on the bed to a reasonable level and I am planning to perforate the plate a lot more to lighten it. I wont be changing the speed until the firmware is stable, without the glitches highlighted elsewhere regarding speed and change of direction.

Best regards

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