How thick does an aluminum print bed need to be

Question

I am extending the bed of my TronXY X3 FDM RepRap printer.

I am extending the bed from 220 mm x 220 mm to 220 mm x 300 mm. For now, I will keep the existing bed and add and aluminum sheet on top. That leaves 40mm on front and back of the original bed.

Right now I only plan on running PLA; but, I do plan on heating the bed.

How thick does the aluminum sheet need to be?

Answer 1

Main factors that control the process of the print bed selection are

• weight: too thick plate increases inertial force, limiting maximum acceleration/jerk (decreased print speed)
• stiffness: too thin plate will warp when heated or bend during calibration (decreased print quality/printer reliability)

For table sizes around 400x400mm I would think of 4mm plate, but it still can warp if heated unevenly.

Sometimes it makes sense to use a sandwich-type table: lower level is MDF, cork panel for heat insulation and thin (1.5-2mm) aluminum heated bed on top.

Answer 2

I build an 18.5" diameter delta printer. The bed was 3/8" thick 6061 aluminum. It is plenty stiff, but it takes an hour to heat to 100°C. When I rebuild it, I'll probably drop down to 1/4" and increase the heater from about 250 Watts to 750 Watts. That should heat the bed in 15 minutes, which is still a long time. Waiting for the bed to heat for ABS is one of the greatest frustrations with that machine.

For your machine, how much the 1/8" plate bends will depend a great deal on which aluminum alloy and temper you use. From OnlineMetals.com, 6061-T6 and 7075-T6 are available. 7075 is slightly stiffer, but both should be good enough. 6061 is half the price.

Answer 3

I highly recommend aluminium tooling plates. They have a +/- 0.1 mm flatness tolerance on 1 meter. It's alloy 5083 offers a great stability. You can purchase such for example at aluminyumburada, which offers custom cut piecees.. They have a minimum thickness of 5 mm, though the prices get lower the thicker the piece is.