SoliForum - 3D Printing Community — Aluminum vs Glass Heated Bed

Re: Aluminum vs Glass Heated Bed

null@example.com (carl_m1968) — Sat, 09 May 2015 04:30:07 +0000

pricecg44 wrote:

Even if the expansion is high it should not matter as the bed will be at constant temperature.
The only issue is any possible cracking of delicate but rigid plastic parts due to contraction whilst cooling.
I quess it would not matter.
Indeed I have had it with bed leveling and the first layer hit and usually miss sticking.
I am going to go for the induction proximity sensors (dirt cheap) with the necessary aluminium bed.
An issue I've found is the one metal heated bed in dx.com says it only goes up the 70 degrees C?

Just slap a 3mm piece of tempered glass over the existing glass and heater. Then do the manual bed level and you should only have to level once a month or when you may have gotten to aggressive trying to unstick a part. I have the opposite isdue of most now and my parts stick too well. Almost impossible to remove until bed temp is below 45c.

Re: Aluminum vs Glass Heated Bed

null@example.com (pricecg44) — Sat, 09 May 2015 04:02:40 +0000

Even if the expansion is high it should not matter as the bed will be at constant temperature.
The only issue is any possible cracking of delicate but rigid plastic parts due to contraction whilst cooling.
I quess it would not matter.

Indeed I have had it with bed leveling and the first layer hit and usually miss sticking.
I am going to go for the induction proximity sensors (dirt cheap) with the necessary aluminium bed.
An issue I've found is the one metal heated bed in dx.com says it only goes up the 70 degrees C?

Re: Aluminum vs Glass Heated Bed

null@example.com (knucklbustr) — Tue, 05 May 2015 03:44:25 +0000

Oldsirhippy wrote:

@knucklbustr - how did you work out the expansion of aluminium at 0.2" for a 200mm plate?
That is a very high expansion.

IT didnt seem right to me too. Engineering ToolBox Linear temperature expansion coefficients online calc.

I would guess more like .005-.006

Re: Aluminum vs Glass Heated Bed

null@example.com (dubbsd) — Sun, 03 May 2015 11:36:38 +0000

My Makerbot 2X has an aluminum bed. I have 500 hours run-time and have replaced the bed 2 times under warranty.
I run at 110°c with Kapton. Because it has 3 leveling screws their is no room for expansion causing it to warp over time
the last plate warped .005" across 9". If i didn't have the warranty I would be printing on glass.

Re: Aluminum vs Glass Heated Bed

null@example.com (Oldsirhippy) — Sun, 03 May 2015 08:27:13 +0000

@knucklbustr - how did you work out the expansion of aluminium at 0.2" for a 200mm plate?

That is a very high expansion.

Re: Aluminum vs Glass Heated Bed

null@example.com (okcazure) — Sat, 02 May 2015 15:36:01 +0000

I have been thinking about an aluminum bed since I have had the original bed crack as well as the replacement borosilicate glass I put in. I believe the aluminum bed would be trouble free and that is why I am interested in it. I would like to hear what others have to say as well!

Aluminum vs Glass Heated Bed

null@example.com (knucklbustr) — Sat, 02 May 2015 15:08:54 +0000

I see that some high end 3D print manufacturers are using an aluminum plate bed.
I cant fathom why.
It cant be expense. Aluminum has to be cut and milled. Glass only cut.

Aluminum does conduct heat quicker than glass, but takes longer to cool.
That may be a problem waiting for the print to pop off.
Aluminum thermal expansion is greater.
A 200mm bed will expand 0.20" from 68F-100C. Glass about .003"
Does that affect a print ?

Flatness- I would bet to guess an average flatness of good aluminum bed is about .003"-.004"
While my Borosilicate glass bed is less than .001"
The OEM DAV glass cracked 3mos after purchase and was concave in the middle.
The new Boro glass seems stronger, harder to scratch and prints come off easier.

Scratch resistance - Manufacturers claim that the Al bed is clear anodized.
My experience, Type2 clear is clear, Type1 clear turns grayish.
Type2 will eventually scratch, Type1 is considered "hard coat". Military uses Type1.
Also, aluminum is more prone to gouging when using a razor for cleaning , lifting.

Anyone using aluminum can give advantages Im missing ?