Glass Bed Attachment.

Check here for useful tips on how to get your printer to print at its best.

Glass Bed Attachment.

Postby konton » Mon Jun 23, 2014 4:13 pm

So I decided to switch my acrylic bed out to a glass one. Mainly because:

1. It was really hard to get the PLA off the acrylic bed. Next time I'll just use painter tape.
2. Sagging on the sides. I had a few ideas but none that would work with those L-Channels.

I choose 1/8" glass (also known as DS glass) from True Value Hardware. Definitely a better choice than single strength and weighs noticeably less than 3/16". I also switched out the L-channel with C-channel from Home Depot. I feel like the sides of the C-channel makes them more sturdy. I used 18" lengths for the bottom railings as well as the glass framing.

IMG_1493.JPG
IMG_1493.JPG (140.02 KiB) Viewed 3978 times


I like the result. I think it looks clean, although that won't matter once the heat bed is installed. To connect the C-channels, I got some smaller M4 bolts and also used hex nuts and washers to tighten them onto the C-channel so I wouldn't have issues when calibrating. I left everything else the same, except took a plastic pipe cutter to the butterfly ends of the nut to turn Mickey Mouse into a sleeping Batman. Those butterfly ears made it impossible to calibrate. But now it's not a problem and with the hex nuts holding the bolts in place. It doesn't move on me like it used to.

IMG_1488.jpg
IMG_1488.jpg (104.93 KiB) Viewed 3978 times


To keep the glass in place I used some picture frame spring clips. That kept the glass away from the end bolt, and pressed it to the top of the C-channel. I did 3 on each side just to be safe.

IMG_1489.JPG
IMG_1489.JPG (127.64 KiB) Viewed 3978 times


Because this is glass, I don't need to put a frame on the sides. No sagging with glass. My future plan is to take an 18x18 Monster Board heat bed and place it below the glass. I'll use the spring clips below the heat bed on the frame to sandwich it to the glass. And I'll add four spring clips on the railings, to add pressure spaced evenly around the center of the board. I placed those in the top photos to give an idea of where they would be located.

I hope this helps someone else with their mods!

Justin
These users thanked the author konton for the post (total 0):
konton
 
Posts: 70
Joined: Sat Feb 22, 2014 11:56 pm
Has thanked: 1 time
Been thanked: 1 time

Re: Glass Bed Attachment.

Postby raykholo » Mon Jun 23, 2014 8:02 pm

Looks beautiful. Added benefit is that if I do this, I'll probably have a messy cut edge of the glass and it won't be visible to the eye because it'll be inside one of the channels!

It took a little bit of re-reading and scrutiny to understand how you handled locking the bolts into the C channel and leveling the bed, but now that I understand, nice work.

Glass definitely allows you to print at higher temperatures, and if you print the first layer above 200 degrees the print won't be bonded to the bed almost permanently, but glass is very fickle when it comes to adhesion and a heated bed definitely will help.
These users thanked the author raykholo for the post (total 0):
Ray Kholodovsky
Owner | Cohesion3D
Cohesion3D.com
raykholo
 
Posts: 213
Joined: Mon Jan 13, 2014 6:19 pm
Has thanked: 0 time
Been thanked: 1 time

Re: Glass Bed Attachment.

Postby DonHanson » Sat Jul 05, 2014 11:48 am

Great design. Looks good.

Did you make the tension spring ribbons yourself or purchase them? If the latter, what are they called?

Nearest match I can find online are half moon tension springs but they'll require enough tweaking that I'm not sure they're worth buying.
These users thanked the author DonHanson for the post (total 0):
User avatar
DonHanson
 
Posts: 54
Joined: Wed Jan 15, 2014 9:32 pm
Has thanked: 0 time
Been thanked: 0 time

Re: Glass Bed Attachment.

Postby raykholo » Sat Jul 05, 2014 12:24 pm

Justin already answered these questions for me so I'll pass on the info:

The full name would be something like "picture frame spring clip" or "metal frame spring clip". I went to Michaels and asked an associate at the framing desk and she gave me a few.

Or some sites if you want to buy online: https://www.google.com/search?q=Metal+Frame+Spring+Clip&rlz=1C1CHMO_enUS567US567&oq=Metal+Frame+Spring+Clip&aqs=chrome..69i57&sourceid=chrome&es_sm=122&ie=UTF-8

The C Channel is .5" x .5" etc... It comes in an 8ft length from homedepot for roughly $10. The 8ft is enough for all 4 lengths.
These users thanked the author raykholo for the post (total 0):
Ray Kholodovsky
Owner | Cohesion3D
Cohesion3D.com
raykholo
 
Posts: 213
Joined: Mon Jan 13, 2014 6:19 pm
Has thanked: 0 time
Been thanked: 1 time

Re: Glass Bed Attachment.

Postby DonHanson » Sat Jul 05, 2014 3:29 pm

Thanks Ray! (& Justin)
These users thanked the author DonHanson for the post (total 0):
User avatar
DonHanson
 
Posts: 54
Joined: Wed Jan 15, 2014 9:32 pm
Has thanked: 0 time
Been thanked: 0 time

Re: Glass Bed Attachment.

Postby sherpa_chris » Sun Jul 13, 2014 6:58 pm

]Don's glass bed modification inspired me to make the change as well though I did mine a bit differently. I wanted to accomplish a few things:

- Avoid wrestling with the printer while trying to scrape off PLA prints.
- Eliminate bed sag.
- Print with ABS or high temp PLA without worrying about first layer fusing to bed.
- Ability to easily remove the bed so I could detach prints without molesting the printer.
- Reduction in total bed weight to ease skipping issues and allow weight for an eventual heated bed.
- Stop my print head from melting holes in the acrylic bed time I homed the Z access.

I used an old piece of broken glass I already had so my initial result looks much less living-room-worthy than Don's but my printer is in the garage so I'm OK. I can easily change out the bed to another piece of glass, the original acrylic or anything else without effecting bed level. This allows me to set a stuck print aside to deal with later while I print anew on a fresh piece of glass.

For PLA, instead of painters tape I use a very thin piece of acrylic taped on the glass. That way I can easily remove the print without any tape sticking to the bottom. I also use less tape and don't have to spend the time to make the tape flat against the glass. The bend of the acrylic helps pop off the print without having to wrestle with the bed while it is attached to the printer.
[attachment=0]New Glass Bed.jpg[/attachment
These users thanked the author sherpa_chris for the post (total 0):
Attachments
New Glass Bed.jpg
New Glass Bed.jpg (202.02 KiB) Viewed 3862 times
User avatar
sherpa_chris
 
Posts: 60
Joined: Thu Jun 12, 2014 1:30 pm
Has thanked: 0 time
Been thanked: 0 time

Re: Glass Bed Attachment.

Postby sherpa_chris » Sun Jul 13, 2014 7:13 pm

This test bed is smaller than the gMAX build size but right now I not printing anything that large. Using the smaller glass saves weight and a larger bed can be swapped in about 15 second. I used the double strength glass that Don mentioned (3.5 mm thick) but have a full sized bed that I will try with single strength glass (2.5 mm thick) to save even more weight. An 18" x 18" square of single strength is about $7 and Lowe's or Home Depot. Lowes cuts the glass for free.

I considered using aluminum C rails like Don but ended up using L rails like the type that came with my printer, though mine are slightly longer on one end of the L ($9 at Lowe's). You could make this change using the top two L rails that currently hold up the acrylic bed though they are a little narrow.

Front rail mount.jpg
Front rail mount.jpg (143.77 KiB) Viewed 3862 times


I drilled holes in the glass using a Dremel tool and a diamond tipped bit so that the glass fits snuggly over the spring bolts. I never drilled glass before but it worked. 3D printing is taking me to all kinds of unexpected places. You could also just clamp the glass (or anything else) to the top of the L rails but then would need to make the bed slightly shorter. I have a clamp shown in the picture but with my drilled holes I don't need it. I can just pull off the glass and replace it with anything else that has holes drilled in the same place.
These users thanked the author sherpa_chris for the post (total 0):
User avatar
sherpa_chris
 
Posts: 60
Joined: Thu Jun 12, 2014 1:30 pm
Has thanked: 0 time
Been thanked: 0 time

Re: Glass Bed Attachment.

Postby sherpa_chris » Sun Jul 13, 2014 7:15 pm

I originally wanted the L rails to bend downward but had to have them facing up on the front of the printer so the bed would clear the stepper motor.

Space for stepper.jpg
Space for stepper.jpg (181.41 KiB) Viewed 3861 times
These users thanked the author sherpa_chris for the post (total 0):
User avatar
sherpa_chris
 
Posts: 60
Joined: Thu Jun 12, 2014 1:30 pm
Has thanked: 0 time
Been thanked: 0 time

Re: Glass Bed Attachment.

Postby sherpa_chris » Sun Jul 13, 2014 7:17 pm

The L rails face down at the back of the printer. The drilled glass is not pretty but it holds the bed in nicely none-the-less.

Real rail mount.jpg
Real rail mount.jpg (188.1 KiB) Viewed 3861 times
These users thanked the author sherpa_chris for the post (total 0):
User avatar
sherpa_chris
 
Posts: 60
Joined: Thu Jun 12, 2014 1:30 pm
Has thanked: 0 time
Been thanked: 0 time

Re: Glass Bed Attachment.

Postby sherpa_chris » Sun Jul 13, 2014 7:32 pm

Printing on a thin piece of acrylic will allow you to complete the sometimes messy work of print removal without jarring the printer and/or harming yourself with a sharp instrument. Adjust the Z axis for the height of the acrylic. Here I've use a small piece for a small print but this will work with any size. This piece was cut from the front cover on an old framed poster. The most expensive part of the whole project was hiring the hand-model to pose for this picture.

Flexible acrylic.jpg
Flexible acrylic.jpg (162.99 KiB) Viewed 3861 times


One final note, I had to add spacers to the spring bolts because the threads did not go down far enough. You can see these in one of the photos. After I completed my first print with the new bed last night I removed the acrylic piece, warped it a bit and the print popped right off.

Thank you for reviewing my nerdy adventure.
These users thanked the author sherpa_chris for the post (total 0):
User avatar
sherpa_chris
 
Posts: 60
Joined: Thu Jun 12, 2014 1:30 pm
Has thanked: 0 time
Been thanked: 0 time

Next

Return to gMax Tips and Tricks

Who is online

Users browsing this forum: No registered users and 1 guest