gMax DoubleWide build in progress

This seemed like the best place to show off my new gMax. I decided I didn't want to lose a working machine, so I started building my own 32"x14"x3" version for the needs of a specific job. I could have given it much more height, but my builds don't require it. Behold, the DoubleWide!

It is really still a work in progress. I need to finish all the wiring and the bed leveling.

One problem I'm having is the Z-Axis doesn't seem to want to reverse. It works fine bringing the extruder up, but it just won't go down. It sounds like it wants to, but the motor doesn't. I checked the pots, threaded rod, and all the wired connections. The only thing I can think of is something with the endstops, which I have yet to wire.

Suggestions are always welcome! If I get this to work, I may try another version with a split y-axis and using all v-slots.



So I wired the endstop and that fixed my problems! Which allowed me to move forward on the build and come up with new problems.

Previously I had a 1/8" glass as a bed. 1/8" glass will bend, and if bending is the biggest issue you have, I recommend 3/16" glass. Of course, now you have a weight issue. And since I was going to just print with PLA, I decided to go back to an acrylic bed. The 5.6mm acrylic you get at Lowe's is pretty bendy. So you really need to brace it with something. I recommend using c-channel pressed against the acrylic.

Considering my bed is 34" wide, it needed as strong a brace as it could get. And it worked. Problem now is that while horizontally everything is pretty straight, bends occur from the sides. Thus the sides also need to be braced.

I'm working on the best way to brace this without having to out and get more c-channel. I think perhaps braces that are not perpendicular could work if set like below. I'd love any thoughts on this.



If I never mentioned it before, this machine is to build fronts onto terrariums. 10g are 10"x20" and 20g Longs are 12"x30". First printing tests were done today building a tee nut. It was perfect on the first try!

A depth test was done printing a 200mm circle. The result was less promising. It managed to make it around and 1mm high, but you can see the bowing. I don't think a 150mm circle would have issues. Since my minimum print width is 240mm, I will try building another brace. The outside frame did not work as hoped. However I was trying to avoid a center brace if I could so I would not lose depth from the screw locations.

The length test went quite a bit better. My minimum print length is 490mm and 500mm worked perfectly with no stress on the hotend. My maximum print length is 730mm, so I decided to overshoot and try 750mm. Around 650mm there started to be stress on the hotend, but it still made it.

I'm going to have to build the braces and lose width. Since my maximum print width is 296mm, I think that should be okay with a current depth of 350mm. We'll see.

BTW I didn't know acrylic melts at 160 degrees. I've never had a problem with melting using the bed I got with my gMax. But now I have problems with the new printer. Any suggestions?




Thanks for the details on your double wide endeavor. Great work. I melted many holes in my original Gmax acrylic bed. Most of them occurred when I returned to the home position while the hotend was still hot. I never printed in that area so it didn't cause any print problems but sometimes the hotend would get melted in place. I solved the problem by switching to a glass bed but you've already done that and switched back to acrylic so that is not the answer. If the corner home position is also the only time you have this problem, you could drill a hole where the hotend hits the home spot. Or, you could tape a very thin piece of metal there. As you know, it's the end-stop that halts the z-axis so you don't really need anything directly under the hotend when it homes. Best of luck with the terrariums.

Thanks Chris!

I love the hole idea! I'm gonna do that when I get home! As it is, I'm out in San Francisco doing a video shoot. But it's not stopped me thinking about how to fix this issue. Are you using 1/8" glass or 3/16"?

I had some time to kill today waiting for my crew, so I went over to Tap Plastics to to talk to someone. At first I asked if a 3/8" plastic frame might be better than 1/4." They told me that acrylic is half the weight of glass, so I might as well get a 3/16" piece of glass over 3/8" acrylic. Then I asked if I was going to keep my 1/4" acrylic bed, should add more 1/2" aluminum beams for additional support? They said if I didn't want to drill more holes through the bed, I'd be better off using weld-on 16 and cementing 1/2" acrylic beams to the bottom of the bed. I never thought of that. That would make the areas where the beams are 3/4" thick acrylic.

So in the end I bought $10 worth of 1/2" acrylic beams and a little bit of weld-on 16. I'll let ya all know what the result is when I get back to Detroit.




I'm actually using 3/32 inch glass (2.5mm). I also have a 1/4 inch bed which is a lot stronger. The 3/32 breaks pretty easily but I've got a bunch of spare sitting around so I thought I'd give it a try. I haven't broken it yet but I'm printing on a thin piece of acrylic placed over the glass so I don't have to stress the glass by scraping things off of it. I wouldn't use the 3/32" unless you can easily remove your bed to pop off prints or you print on something else placed over the glass as I do.

Let us know how the acrylic rods work out. Good luck with it.

I'd avoid 3/32. That's always some thin glass. I always go at least 3mm which is also 1/8". That works for most anything I build. But 3/16" can also be good if you need it big and flat. 1/4" glass can be an overkill.

5 bars fixed my issues with the 14" inches in depth:

But now the sides are sagging with the weight. I should have gotten 2 more 34" bars to replace the aluminum. Still, it seems to be good enough to starts my first 10x20 prototype:

I'll let you know how the end result looks.
To finish my DoubleWide story...

It tuns out the side aluminum weight was not the problem, but the pressure they caused between the other sides of aluminum. Long store short, I removed them, and now I can print flat 10" by 20" with no problem.

Of course with forward momentum comes new problems. And that was a weird hanging issue that happened around hour 3.5 of a 10 hour build! Augh. It happened usually in the middle of the night or when I was having lunch. I wasted about 5 pounds of plastic until I solved this problem. It turns out the problem was caused when the extruder goes as far right and then left as possible. The filament would losen and then flip off the spindle. Which caused the filament to get caught around something on the roller and thus destroy the whole printing process.

All this was due to too much of an angle for the filament to be pulled from. The solution to was make sure the filament would never be pulled at that angle. I took the simplest road to solve this and moved the filament roller 2 feet straight up.

Works great, but now I need a ladder to replace the filament. Good thing I only print in black!



HAHA thats pretty funny. Something I would not have thought of being a problem. Do you think you could just turn the rollers and filament 90 degrees? I guess that it could unroll a lot as it goes back and forth.
Yeah changing the angle by 90 degrees would just make it jam faster, and putting the whole thing on it's side wasn't a solution. But I had 2 foot 1515 t-slots by 80/20 around still, so I thought I'd make good use of them this way.

About to test printing with ABS tonight. I think I'll need a heated bed of glass, but might as well see what happens.

Turns out I didn't need it. Please keep in mind I'm printing something mainly empty in the middle, but it's almost 500 x 240 mm. That's quite a bit that is just pressed flat on the bed.

At 225 degrees the ABS started coming off the acrylic in a few minutes, but at 235 degrees it stuck and stayed in place even 2 hours later. Yet it still came off the acrylic bed easily. Unfortunately I left the fan on in slic3r and as such the successive layers were added at around 205 degrees, not the 245 I set it for (I think I'm going to try running it at 250). That messed up the rest of my 8 hour build, but allowed the testing I needed. My results told me that PLA was best for my build because of the rigidity. ABS is way too bendy for me.

BTW for anyone who cares I was using ABS from Toner Plastics and sold by often on sale for $15.95 a kilo. Generally I get PLA for about the same price, which requires with the current firmware, a first layer at 202 and successive layers at 212.
The first thing to do during an earthquake is run out and grab your filament before it topples and breaks the glass bed. Next, make sure your family is all right.

But seriously, it looks like one false move and your reel could smash your printer. The chance of this happening is small, but with all the work you've put into the custom bed it would be a shame to loose it all because of a jostled reel.

I've had a number of issues with filament jams similar to yours, and I've just got a regular GMAX. Somewhere I've seen a round filament guide for the upgraded GMAX filament roller but it doesn't seem to be in the download section. Right now I'm using a couple of pipe cleaners to guide the filament as a temporary fix.
The filament would losen and then flip off the spindle. Which caused the filament to get caught around something on the roller and thus destroy the whole printing process

Are you able to restart the print after the filament jams like you mention above? I assume that this problem just stops any filament from coming out but everything below the problem is OK. You most likely already know this but others may not, you can restart a failed print by modifying the G-Code. I've done this many times and often can't even tell where the jam occurred. I've saved a ton of plastic and re-printing time. I won't burden this post with directions for something that everyone already knows, but if there is anyone who does not know how modify G-code to re-start a failed print, reply to this post and I'll respond with some instructions.

Well saturday I turned the fan all the way off, and that overheated the system and melted the entire extruder system. But no worries. I printed what I needed with my gMax 1.0 and I'm back on track.

Yes, as long as nothing beyond the print is actually destroyed, I'm good to try and try again. Usually the print by the time I get to it is long done and past the point of fixing. It's pretty mangled.

At the moment I've updated the firmware and slic3r files. Great for my DoubleWide. Not so good for my gMax 1.0. It seems to be extruding too much during a print. I'v tried reducing the flow, but that doesn't seem to help. I'd try fixing it, but I'll be replacing the head with an all metal one shortly. However any suggestion would be great.

Chris, my DoubleWide uses acrylic. I thought you knew that. So far the ABS adheres well somewhere between 230 and 235 degrees. I've got not heated bed, but the only problems I've notices is perhaps I need to raise the temp after the first later to 250. I'd like to make sure the layer sick together properly.


I forgot that you have the acrylic bed, despite all of your documentation. If an earthquake hits, I'll recommend that you kneel under your well constructed double wide for protection.

sherpa_chris said:

If an earthquake hits, I'll recommend that you kneel under your well constructed double wide for protection.

Bahahaha!!!! As a Californian, that just seems all to realistic to me. Maybe gCreate can latch onto that for marketing; "in the event of an earthquake, your gMax also doubles as personal protective gear." Happy Monday!!!!