Bit late to the party, but I'm starting to gather materials...

So... I've been lurking around the 3D Printing community for several years now and seemed to have settled on Nops Mendel90 a couple of those years ago. Excuses for not following through were plentiful, but now that I have the time and attention for locally sourcing parts...

As it stands I've contacted a local to print me the plastics for an estimate of $100 for the set, but I still need to sort the essentials from the not on that. I'll likely not bother with the spool holder, fan guard and similar to keep initial cost down and to give me something to do once the printer is running. I've sent off for some quotes for the ACM frame, but failing that will likely order a sheet of [www.ebay.com]

I'm currently stuck on all the variables that go into the self-sourcing of parts... I don't want to give my printer the go-ahead until I'm sure later changes won't trip me up and box me into paying a premium on a part that I have to have else being faced with backtracking to rebuild (rework is expensive).

I guess what I'm looking for is direction on what order I should be pursuing getting parts... I don't want to get parts printed then realize later the parts I had printed don't work with what ever hotend I get. Or having the small difference between 3mm and 1/8" kick me in the kiester later. Or needing to add wires to the hotend PCB or adding conductors to the ribbon cable making me have to reprint wire stays and drill new holes in the otherwise pristine frame.

So... who wants to ask me questions to make me think about things in the right way so I can hopefully wrap my head around this?

(It's been said before- Special thanks to Chris and Mary for all they have done to help this project mature. If we were on the same continent I totally would have ordered a kit and been well down this rabbit-hole years ago. Thank You.)
((Thanks to the community as well for helping give Chris direction and support through it all.))

Okay. Not very fair on my part... I'm supposed to come here with questions, not come here and make you guess what information I might find useful. I just tend to write walls-o-text and that was an attempt at sparing you all that So... more pointed questions towards what I'm actually wondering, thoughts below...

1. JHead or E3D?
2. 3mm or 1.75?
3. Suitable grade for smooth rod?
4. M3 cap screw x 10mm?
5. "Might be able to slice on the Raspberry Pi"?

JHead or E3D? - I feel I need to sort this before I give the go ahead to my printed parts source... I guess my question is what do you get from E3D at twice the price of the JHead? I'm all about maximizing the quality of prints where I can but saving money where I can also sounds good. One thing that confused me was the JHead description stating a fan was needed for PLA... I thought ABS was the complicated material that needed higher temps and an enclosure. Vent fans for fumes and such?

3mm or 1.75mm? - It seems to me that over time there has been a leaning towards 1.75mm filament, yet the M90 defaults to 3mm. If the only thing that /really/ matters is the size of extruder you buy then I'd probably lean towards 1.75mm. Sell me on sticking with 3mm.

Suitable grade for smooth rod? - I haven't seen any specific industry specs as a minimum grade to look for. I'm fond of Stainless Steel so my natural draw is in that direction. 303? 304? 17-4? Does it really not matter all that much? Even though I'm aiming for a Dibond Mendel I've already decided to go with 10mm (or the closest Imperial sub-equivalent) rods. If the Sturdy goes up to ten then I feel its a marginal distinction and a worthy early upgrade.

M3 cap screw x 10mm? - Written as it is in all the docs there seems to be a missing variable. HomeDepot lists M3-32 x 20 mm. and M3-0.5 x 8 mm. BoltDepot lists theirs in the format of 3mm x 0.5mm x 16mm. I'm thinking the 2nd place is height of the cap maybe?

"Might be able to slice on the Raspberry Pi"? - In reading all the other threads I remember seeing brief discussion of the Pi potentially being able to slice, but at a very long time... Which Pi was this written in regards to? Pi1? ...If so and with the introduction of more powerful Pi, has this changed? I expect slicing on a Zero would be just as impractical as if the above had been written in regards to the 1, but would slicing on a Pi2 or new Pi3 be considered a workable solution? I like the added GPIO functionality a Pi could bring (camera, controllable bed lighting, fans, stuff) and will probably be including one anyway.

Edited 1 time(s). Last edit at 03/16/2016 06:18PM by m_pan.

1. E3D if you want to print plastic that needs a temperature higher than 250C. J-Head if you want to print PLA.

A print cooling fan is needed to print PLA and that also cools the J-Head. PLA goes soft at 55C so you need to cool the previous layer below that temperature and keep the top of the hot end below it. E3D needs a separate hot end cooling fan, different Wade's block, fan duct and fan bracket.

2.The standard design only supports 3mm. For 1.75mm you need a direct drive extruder. There is a recently added option for that but it it hasn't been tested with a NEMA17 and a commonly available drive pulley.

3.The smooth rods should be h6 tolerance precision ground induction hardened steel. These are the ones we used for the kits [www.marchantdice.com]. If you use imperial then you will need to find imperial linear bearings. The sizes are not close enough to mix them and keep within the tolerance to give the correct pre-loading.

4. The 0.5mm is the thread pitch and is standard for M3. M4 is 0.7mm, M6 1mm, M8 1.25mm. These are known as course pitch. There are fine pitch versions but not commonly used. -32 would normally be threads per inch for imperial screws, so I don't know what M3-32 means. I think it must be a mistake as 32 tpi is too course for M3. The screws for the ATX PSU are No 6-32 pan screw x 9.5m which are imperial UNC threads with 32 threads per inch.

5. Yes OctoPrint supports slicing with Cura on a Raspberry Pi but I have never tried it. Obviously it will be a lot faster on an RPi3 than on an RPI B and RPi2 will be somewhere in between.

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[www.hydraraptor.blogspot.com]

i went for the 1.75mm E3d for mine because:

- i wanted to print exotic materials
- 1.75mm filament has a smaller bend radius so suited my plans for enclosing the printer slightly better

i was able to use the 1.75mm filament with the original extruder, but one printed for 1.75 did improve print quality for me

Quote
nophead
1. E3D if you want to print plastic that needs a temperature higher than 250C. J-Head if you want to print PLA.

A print cooling fan is needed to print PLA and that also cools the J-Head. PLA goes soft at 55C so you need to cool the previous layer below that temperature and keep the top of the hot end below it. E3D needs a separate hot end cooling fan, different Wade's block, fan duct and fan bracket.

2.The standard design only supports 3mm. For 1.75mm you need a direct drive extruder. There is a recently added option for that but it it hasn't been tested with a NEMA17 and a commonly available drive pulley.

3.The smooth rods should be h6 tolerance precision ground induction hardened steel. These are the ones we used for the kits [www.marchantdice.com]. If you use imperial then you will need to find imperial linear bearings. The sizes are not close enough to mix them and keep within the tolerance to give the correct pre-loading.

4. The 0.5mm is the thread pitch and is standard for M3. M4 is 0.7mm, M6 1mm, M8 1.25mm. These are known as course pitch. There are fine pitch versions but not commonly used. -32 would normally be threads per inch for imperial screws, so I don't know what M3-32 means. I think it must be a mistake as 32 tpi is too course for M3. The screws for the ATX PSU are No 6-32 pan screw x 9.5m which are imperial UNC threads with 32 threads per inch.

5. Yes OctoPrint supports slicing with Cura on a Raspberry Pi but I have never tried it. Obviously it will be a lot faster on an RPi3 than on an RPI B and RPi2 will be somewhere in between.

1. That tells me that I should be looking at the E3D hotends more then. Good timing because I was seriously considering buying a JHead last night. I have a MicroCenter about an hour away and was thinking about making up a reason to go so I could pick one up. So if my planned first prints were ABS replacement and upgrade parts then I should be looking at the E3Ds?

2. Is this 'recently added option' the nema14 of the Huxley90 variant? Did you use the 1.0 version of [shop.arcol.hu]? How does it differ?

3. I don't want to use imperial. If I'm building a house or furniture then sure, but I can recognize when a different system is superior. And I need the practice. Especially at this stage, I prefer to buy the right thing than to introduce inconsistent variables.

4. Thread pitch. Makes perfect sense. See what happens when you write and think without thinking? ...and yeah, I'd not be surprised if 32 was a misprint. It is HomeDepot afterall.

5. No point really considering the Pi2 at this point unless I see it on clearance at MicroCenter. But it was more if the speed is nearing something actually practical. I'd likely leave it with an old monitor, kb and mouse and do all the setup at the printer. It'd be nice if it was on the scale of 'start slice, pickup work area some, start print, go do something else for a bit'.

Quote
alkempster
i went for the 1.75mm E3d for mine because:

- i wanted to print exotic materials
- 1.75mm filament has a smaller bend radius so suited my plans for enclosing the printer slightly better

i was able to use the 1.75mm filament with the original extruder, but one printed for 1.75 did improve print quality for me

I see the benefit of 'exotic materials'. Added capability is always good. Since JHead and E3D are the two 'out-ofthe-box' solutions is it a question of:

JHead - does PLA well, ABS if you treat it nice and promise it breakfast in the morning?
E3D - If you want your printer to take whatever crazy filament sample that shows up on your door step?

What kind of bend radius can you get? Right after I get my printer built I plan to enclose mine as well... "Awww. ...Cute little Android... Now- how am I gonna box this in?" So I doubt I'll be using the 'over-the-gantry support' spool holder. It'd be nice to not have a spool sitting on top of the box so I was wondering if it could make the turn from the back of the gantry and back down into the extruder at the top of the Z range... Maybe add an inch or three to the top of the gantry and supports to give it more space and to clear the Z-rods on the left. Make an elongated hole where the tube goes through the gantry sheet to give it a less constricting path? But again- might not even be considerable from the strain of the head traveling along the X.

Edited 1 time(s). Last edit at 03/17/2016 09:07PM by m_pan.

1. No a J-Head is fine for printing ABS. All the kits were printed with J-heads at 255C for the first layer and 250C for the rest but coloured ABS needs a lower temperature. It is also better for printing PLA than an E3D due to the PTFE liner all the way down and I would expect it to be better for flexible filaments. E3D can handle some high temperature exotic materials and has interchangeable nozzles. I have no experience of using them.

2. The one I used has an outside diameter of 8mm. I got it from the Indigogo campaign but I don't think it is available now. The bigger one might work with a NEMA17 but certainly not with NEMA14 which was a bit underpowered even with the smaller one.

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[www.hydraraptor.blogspot.com]

1 - Aargh. I go to bed thinking I have a plan, then I wake up to something that gets me thinking in a different direction. My plan when I set out was to make sure I was willing to spend extra on certain core parts (hotend, rods, frame and electronics in my case) and to stay away from clones where ever possible. But now I'm rethinking that a bit. Since one of my goals is to work up to never having a reason to have my machine to be 'down' due to a broken part which means on-hand replacements. Plastic parts, spare electronics, etc. I'm thinking it might be better to build to spec then change things later... Much as I don't want to , I might want to reconsider my stance on clones if even just for the sake of building component inventory. It also seems that the E3D clone market also has a few aesthetic options available that the genuine doesn't offer. So I guess MMMV from here. [edit] I'm thinking I might actually go with a MakerGeeks custom [www.makergeeks.com] ; it's an all metal JHead so I can have the default JHead configuration printed for me but get some of the E3D benefits out of it.[/edit]

2 - I'm thinking I might stick with 3mm and leave 1.75mm as a later conversion when I have extra parts and the ability to print rather than bootstrap adjustments.

Edited 1 time(s). Last edit at 03/18/2016 04:38PM by m_pan.

the bend radius is entirely dependant on the filament used, but is tighter.

i would think carefully about using clones, they have benefits granted, but if nobody buys the originals it slows development.

In terms of enclosing the mendel90, building to spec would make it more difficult as it wasn't designed to be enclosed. You should consider how you would enclose it if you built to spec or what changes you could make up front to make later modifications easier. As an example, increasing the base sheet space at the rear of the printer would allow for a rear panel to fit without as many cutouts.

Quote
alkempster
the bend radius is entirely dependant on the filament used, but is tighter.

i would think carefully about using clones, they have benefits granted, but if nobody buys the originals it slows development.

In terms of enclosing the mendel90, building to spec would make it more difficult as it wasn't designed to be enclosed. You should consider how you would enclose it if you built to spec or what changes you could make up front to make later modifications easier. As an example, increasing the base sheet space at the rear of the printer would allow for a rear panel to fit without as many cutouts.

re: bend radius; changes before, mods later; - I've actually got a couple of thoughts in the enclosure area. Since I can apparently get 2'x4' sheets of aluminum composite delivered for ~$33US I'll have off-cuts that I hope will be enough to work a sub-enclosure between the gantry supports in the area of where the spool usually sits to the back of the machine then put the entire machine into an outer wood and plexi box that vents gases and pulls cool air into the electronics. That aside... when I was considering filament size and hotends I briefly considered 1.75 and a remote bowden, maybe running the tube through an elongated slot in the gantry frame and driven by a stepper mounted behind the frame on one of the support panels... but then I was like 'How `bout maybe not right now? `mkay?'.

re: clones - I get the argument. Totally. But as I wrestle with sourcing the parts and the intention of building a second printer it occurs to me that things like hotends are really just something that needs to be experimented with. Best way to do that is to have parts on hand... and since hotends and plastic historically don't work well together an all-metal one seems to make sense, for now at least. But yeah... that's part of why I settled on the MakerGeeks metal bowden. The other part is that they are almost local to me... other side of the state, but still... I'm looking forward to trying out their house brand filament because support and stuff.

So... heated bed. Aluminum Mk3 or CopperMk2B? I'm torn because '...Mk3, it's newer and has to be better then, right?' and Mk2B because it's copper and seems like it'd more thermally stable, like in a 'mass retaining heat' kinda way?

[edit] For now though I get to wrestle with runtime crashes when I try to run the build script. Maybe tomorrow I'll try on a desktop instead of my driver-bloated netbook.[/edit]

Edited 2 time(s). Last edit at 03/19/2016 10:34PM by m_pan.

i went for the aluminium heated bed, takes longer to warm up but i found it much easier to keep level as it doesn't flex so much. i still use a sheet of glass on top, mostly so i can change out different prepared beds for various types of filament. my heated bed takes around 16 minutes to heat up to 90C compared to around 6-7 minutes with the one i got from nophead. I will add that they are a pain to solder as they act as a massive heat sink.

In terms of stability, i would edge towards the aluminium bed, but that is because the copper variant flexed and didn't make full contact with the build plate (glass).

Better is subjective, both would be good choices. If i were doing it again i would still go for the aluminium bed.

Quote
alkempster
i went for the aluminium heated bed, takes longer to warm up but i found it much easier to keep level as it doesn't flex so much. i still use a sheet of glass on top, mostly so i can change out different prepared beds for various types of filament. my heated bed takes around 16 minutes to heat up to 90C compared to around 6-7 minutes with the one i got from nophead. I will add that they are a pain to solder as they act as a massive heat sink.

In terms of stability, i would edge towards the aluminium bed, but that is because the copper variant flexed and didn't make full contact with the build plate (glass).

Better is subjective, both would be good choices. If i were doing it again i would still go for the aluminium bed.

flex;sag - Are you using a 3-point or 4-point mount? I'm leaning towards 4-point since I don't expect to be super-mobile with my printer so I shouldn't have to worry about releveling /all/ that much. An eventual z-probe makes leveling that much less of a concern. I plan to print on glass whichever direction this goes, so printing directly on the heat bed doesn't really sway me a whole lot.

heat - I find it a little odd that the aluminum takes longer to warm up than the copper.... makes sense though. Heavier density metal is easier to saturate and aluminum just begs to give some of it's heat to every little air current that passes by. Any chance you noticed any change in the duration and frequency of the heat cycles to maintain a set temperature? I'd expect longer duration, less frequent from the copper...

also - I'm thinking this looks kinda appealing - [reprap.org] and my CDO will probably force me to find a way to reverse the heat bed so the text faces front.

i am using a four point mount, as per the original nophead design. The four point mount is, however, more bothersome to setup compared to the three point.

The aluminium takes longer to heat because it has a bigger thermal load (i.e. there is more of it which has to heat up) this means it will require more power, and because this can't be applied straight away, takes more time to reach the same temperature. It also appears to be exponential, in that the higher the temp the significantly greater time it will need to heat in comparison. The heat cycles and frequency do change. Because of the higher thermal mass it is also better at retaining heat (slightly) and also needs more time for changes to take effect. This results in a really smooth temperature curve where i havn't noted a large variance in temperature during printing.

I did something similar to this, although i used SMA headers instead because the aluminium heatbed has a pad. It works really well, but clearance was an issue for me, i am currently investigating different right angled connectors which may provide better clearance.

I'll gladly trade less flex and sag for a more bothersome setup. Ultimately I want my print surface to be flat and given the manufacturing tolerances of heatbeds a 4-point seems a better option if quick leveling doesn't sell me. Once finished I see my printer being about as mobile as the table saw out in my shed and I've *NEVER* felt the need to load my table saw into my truck and take it out for a drive ;P.

Hrm... seems like I've been drastically underestimating the quality of the aluminum metal used for the Mk3 beds...

SMA connectors? Really? I don't know if that option would have _ever_ crossed my mind. I was thinking a dremel and a tiny, tiny drill bit. My thought hadn't progressed so far as to using a right-angle header however, so I'll probably take that into consideration when the time comes.

Bear in mind, i havn't really looked at the 3-mount variant because the kit was set up for four pin.

The aluminium beds are 3mm thick, quite a bit of mass there, however, there would be nothing stopping you from throwing additional heating elements on to it such as a silicone heater pad, wire wound resistors etc to speed up heat up time. You would, however, also have to beef up the cabling going to it as well as the power supply you use.

typo, SMD connectors! Something like: [uk.farnell.com]

usually rated for 1A per pin i put a 5x2 on mine

Aye. But all the arguments for 3-point revolve around 'as good as' and not 'better than'. If I thought it would be practical and help print quality I'd go with a 12-point ;P

I just thought they'd be a low quality aluminum alloy. I can deal with pre-printing warmup time, I'm far more concerned with the stability of the temperature. Probably comparing mandarins and tangerines in the end on this one... amazon aluminum Mk3s are ~$10, Copper Mk2Bs are ~$20. Maybe I'll reconsider the aluminum at half the price.

SMD... lol. Makes a bit more sense... Having to thread the connectors wasn't making much sense. But board-edge made all kinds of sense ;P Yeah... right angle seems to be the way to go on this though. I just don't know I trust surface mount on this considering the stresses it could see would be lateral which is where the method is weak. I groan at the idea of drilling 20 holes through 3mm of aluminum or copper on a tightly spaced grid but it can be done, just requires mustering the effort.

5x2 is all you could fit on the pad, yes? Not enough space for 6x2?

the mounting is strong enough, remember that the ribbon cable feeds through strain relief, no risk of it working loose

you probably could go 6x2 but 5x2 gave me 10A of connectivity, plenty with a bit of fudge factor . One consideration is the connector you use on the other side, because the plastic shroud of the connetor is large compared to the pad separation there isn't much clearance, mine has about 2mm gap between connectors when fitted. That being said, you would have more room if set up for 24V instead of 12v

Quote
alkempster
the mounting is strong enough, remember that the ribbon cable feeds through strain relief, no risk of it working loose

you probably could go 6x2 but 5x2 gave me 10A of connectivity, plenty with a bit of fudge factor . One consideration is the connector you use on the other side, because the plastic shroud of the connetor is large compared to the pad separation there isn't much clearance, mine has about 2mm gap between connectors when fitted. That being said, you would have more room if set up for 24V instead of 12v

I was worried more about plugging and unplugging just in case I get a stiff header plug. Heat softened solder worries me a bit as well as a mechanical fastener. Through-hole just seems safer. But hey... surface is working for you so I'm willing to accept a bit of over-engineering on my part

Hello,

There is no such thing as an "all-metal J-Head". J-Heads are designed with high temperature insulators so as to keep the heat where it is needed. The "all-metal J-heads" are chinese knock-offs and not made to any specification.

Real J-Head hot-ends are made in the USA.

Best Regards,

Brian

I took it as a reference to the mount style. I understand the difference between, say, an authentic Zippo vs. a stamped chinese knockoff. As it applies to this instance- I'm more concerned about capability to try diffrerent filaments while sticking close to the original mendel90 design. I just worry about having plastic *inside* the barrel.

Once I'm up and printing I can see having different hotends preconfigured for different materials. Maybe a legit JHead with a .35 nozzle for PLA.

Ordered my AlumComp today. 4'x8' sheets @ $32.66 shipped. [www.ebay.com]

Having the frame cnc-milled has proven to not be worth the effort of finding a place to do a one-off production, much less having options to price compare. Hand cutting the panels accurately shouldn't be all that hard, I'll just have to take my time with the drill patterns. Given that I can't just run down the street and buy the comp. I was already thinking I should get 2 sheets so when the seller had an 'extra 15% off when you buy 2 or more' promo... I think I should be able to get an entire frame from each sheet.

I'll need to add a package of utility blades and metric drill bits to my bom.

it would be great to see photos as you go

1. Plastic
2. Hardware
3. Rods
4. Rods (pt. 2)

(1) I've been assuming yes- but if my first parts are in PLA will the extruder block plastic last long enough to print it's own replacement in ABS?

(2) So, ...hardware... the BOM is a little vague on this one..."m3 cap screw" and "m3 hex screw" are seemingly the same thing- at least according to google image search.

Could this ( V V V ) style be used for both descriptions or does one /have/ to be of some other style?


(3) What is the exact (real) diameter of the 8mm extruder idler bearing axle rod? Since I'm using 10mm linear rods I won't have any 8mm off-cuts to get a tiny 22mm piece from so I picked up a couple 3" 5/16" bolts that I'm planning to cut the threads and head off of. By going through the drawer and measuring bolts from different manufacturers I was able to find what are apparently thick 5/16" that were a couple hundredths over 8mm through the bag. I realize this really depends on the exact ID of the bearing and the tension of the assembly on the filament itself, just wondering if I'm in the neighborhood with the 5/16" bolt shaft.

(4) Just because I'm upsizing my linear rods to 10mm... there's no reason to upsize my threaded rods beyond the standard M6, correct?

1) I think you will need to add a small fan to keep the extruder and carriage cool.

2) No they are not the same. Your picture is a cap screw. A hex screw has a hexagonal head.

3) The hole in the 608 bearing is exactly 8mm so if the rod is bigger it won't fit. I use h6 8mm rods and they have to be hammered in but it wouldn't matter if it a loose fit.

4) No I have built a machine with 10mm rods and 6mm screws.

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[www.hydraraptor.blogspot.com]

1) Not totally unexpected. I was assuming as much- just wanted to make sure I wasn't going down a dead end by having my first set printed in PLA.

2) That's what I thought (the hobbed bolt was a good indicator). I've just taken to googling terms to make sure I'm thinking what another meant. ( I get it... a lot of online listings are using the 'hex' in place of 'allen' in reference to the drive. Just getting questions out of the way before I end up with a bunch of the wrong fasteners that'll end up making that particular tool box heavier.)

3) I figured loose would be tolerable, it's why I was okay with ~8.02mm or so including the rather thick (for a bag with one bolt) plastic. Good to know that I can go back for one of the slightly less than 8mm thick 5/16" bolts.

4) Didn't think there'd be cause, but wanted to make sure I wasn't over looking some odd factor. I wouldn't be surprised if 8mm really was sufficient for a dibond, but would you go so far as to say the 10mm linear rods are a wasted 'upgrade'?

5) Has anyone tried the styrene\acrylic 'glazing' from the diy poster frame kits as a substitute for the polypropylene? Material and perceived thickness make me skeptical it can do the bend under the bed without breaking. -> [www.officesupply.com]

edit: 6) Steadily progressing and nailing things down and I'm about to decide on smooth rods- got it narrowed down to two options I think:

Group1 - [www.mcmaster.com] - Narrowed down by browsing using Nopheads h6 tolerance as a guide
Group2 - [www.mcmaster.com] - Just when I thought my mind was made up I find\reread a McMaster parts list off in a sub-forum that pointed to the 8mm version of these.

So, Group1 is about 3x the cost of Group2. Is it worth it? (the stainless rods are still whispering to me, but I think stainless will have to be satisfied with threaded rods (fwiw- I think these [www.mcmaster.com] are going to be my threaded rods.)

Edited 4 time(s). Last edit at 04/08/2016 03:23AM by m_pan.