Deflection in precision rod rails

[Lee Roberts]

12mm probably good enough for a PCB miller on the X-axis supporting the table, with 16mm on the Y axis and 12mm on Z.

I'm about to start work on a mill i plan to use for PCB's and 12mm rail was the choice, i have rail to hand and so i can use other sizes at what point would we not see any deflection, with this info i could work out if the weights i plan to move would be a problem on 12mm rails ;-) keep up the good work !

CM

[irving2008]

there will always be deflection.... the question is at what point does the deflection become to small to be of interest.... clearly if you are aiming to mill Ali to .01mm tolerance you need something that wont deflect more than .005 under cutting load.... remembering that deflections combine... movements in gantry, table, etc all add up...

[irving2008]

Just to answer the point made previously, now the rails are fitted and bolted up tight with the table attached, the deflection of the centre of the table (16mm rails) under 4.5kg of load is <0.05mm (so that is the combined deflection of the rails, the MDF table and the MDF base the rails are mounted on).