as for myself, just returned this evening to canada.
tomorrow is business as usual.

 

Great build! This one looks to be much more my speed, particularly the use of off the shelf parts instead of a crapton of printed parts.

A few questions, hopefully you guys wouldn't mind helping out with.

1) Regarding weight - for those of us who are going to use not only slightly smaller dimensions, and a single E3D v6 hotend, is the 2040 rail for X and Y truly necessary to hold without bowing? I read above where you guys were lifting like 13 pounds, and I wonder how much of that could be reduced by dropping some rail weight?

2) Same question with the Z guides. Considering the lead screws are carrying the overall brunt of the weight, it seems like those rails are really to keep the ends of 1 axis from twisting and just rolling nicely up a guided rail. Since those pieces aren't structural, is there a need for 2040 rail in that particular instance?

3) What are your thoughts on moving the Z motors and belts to the top of frame? Having pulleys above the frame above the top bearings allow one to easily replace a closed loop belt without having to take the lead screws off. Also, considering reduction in the gantry weight with #1, it seems like a single motor driving larger lead screw pulleys on a single loop would be preferable from a keeping motors synced standpoint.

4) What about converting to a corexy style system? Seems like reducing the motor count by 1 would help with both reduced Z lifting weight and (from what I understand) increased speeds?

5) Will you be posting an updated BOM list?

 

Question: How much does the frame wobble? Look like a big frame and from what I know aluminium isn't the sturdiest material out there...

 

uh, steven, second picture from the bottom...is that the panic button from an iphone?

 

teasing aside, i love your work, guys.
looking forward to see a video of it in action.

 

can it move in Z? have you got a video of that! Pretty cool!

 

Here is a new vid testing homing X/Y and Z movement...

 

Thanks, Mark.

Installed the 26" boro glass, heat pad and 1 hot end...

 

can't wait for my chunk of glass to show up this week.
until then, dry tests..

 

Here is a video of the printer homing X/Y/Z and auto bed leveling...we are really almost there...

 

that glass looks so good on the bafp it makes me drool..
my glass is coming today, brought by a buddy of mine.
beer is already cold, can't wait to finally see how the glass sits on the bed, after 2 years of work.
will post pictures soon, hopefully tonight if sober.

 

well, glass came as promised, better post some pics before that beer bottle becomes a 12 pack.
***, after a hard day of work...

 

glass weighs around 90 lbs.
platform is calculated for about 550 pounds, and each lead screw is good for about 250 lbs.
it runs great, the frame is reinforced by design, plus an extra two top rails (black) so there's no shaking while running.

will post more vids soon.

 

well, if my math is any good, glass density is 2500 kg/m^3
my glass is 1332x1170 mm, 12 mm thick, which means a volume of 0.0187 m^3.
multiplying that with density we get approx. 46.7 kg, or 102 lbs.
i was worried the glass will have an inherent bow from tempering, but the glass guys did a really good job at keeping it straight.
special order, only 250 canadian bucks plus a six pack for shipping.

 

speaking of glass, does anybody know where i could find some flat and round thermistors? the diameter would have to be around 5 mm max, to fit the 10 mm pass holes i allowed in the silicone pad especially for this purpose.
the thermistors i have look more roundish and i am concerned about the contact patch with the glass. i'm hoping flat thermistors (thin film, maybe) will do a better job. thanks.

 

hi justin, i'm hoping to find some small coin shaped thermistors, i have 8 pass holes, 10 mm diameter each, cut into the silicone pad especially for that.
the coin, or disc, shaped thermistors, ensures a better contact patch with the underside of the glass.
not so sure cylinder shaped thermistors would be that good at it.

https://vikiwat.com/userfiles/productimages/1169/product_large_35992.jpg

 

i think i will enclose the thermistors i have in a little plastic tube, and run the lead wires down thru one inch of the cork insulation supporting the pad. the top of the thermistor will be flush with the top of the enclosing tube, and in contact with the under side of the glass. the silicone pad has eight 10 mm (3/8") diameter pass holes for an equal amount of thermistors, four in the corners and four around the center.
in retrospect, i could have designed those holes somewhat larger, but i didn't want to bite too much into the heating area surrounding them.
next heated pad will have a better design.

 

uh, just enclosed the thermistors in 3/16 shrink wrap. and since the lead wires are about 1 3/4" long and the cork it's going to go into is only 1 inch deep, it all works like a charm. the rest is just laying wires.
couple of pictures attached, before and after.

 

indeed, i used the shrink as a sleeve, and pulled it over both legs from the open end, then onto the thermistor itself, so both legs, or lead wires, are inside the shrink wrap.
these lead wires come out of the thermistor at a divergent angle and the metal in them is quite steely, so they preserve a natural rigidity inside the shrink wrap. also, there is a space of about 3 mm (1/8") between them, but i've been thinking to insulate the lead wires separately prior to covering them, to prevent them from touching each other accidentally.
the initial idea was to use some plastic tubes, 4 mm (5/32") inside diameter and 1 inch long, but then my sights literally fell on the shrink wrap tube laying around, and i said 'why not'.

 

Recent progress...