Re: Yet Another Ord Bot Project

[Dinesh Kantheti]

Hi Nat,

Good to note that you have also preferred Ord Bot.  Not sure if you had a chance to see my post. 

I have tried to source it from different suppliers to see if I can get the cost down. However it doesn't look like it.  It is costing more to source the hardware separately.  Please visit my post for my updated cost sheet. I took some inputs from your costing (Billiby parts). Both are coming very close jut $10-$15

I think you have to include Heat bed additionally in your costs.

I will wait for Garry's confirmation, but I think the carriage is good enough for Wades extruder from extrude3D.  (I got my extruder and hot end from Extrude 3D)

Will see on Monday at 3D printing night

Regards,
Dinesh

 
On Thursday, 15 November 2012 23:11:42 UTC+11, Nat Allan wrote:

Hi all,

After my first visit to the hackerspace last 3d printer meet, Ive started sourcing parts for a 3d printer as ive been interested in building one for 2 years or so.

I loved the sturdy design of the ord bot so I have ordered one from ATI.  Its what ive wanted to see come out of the 3d printer community.

I have built a spreadsheet of parts ive decided on and suppliers as i intend to start purchasing in the next week.  Id love any feedback on it or any issues ive overlooked with fitting, as well as good local melb suppliers for parts that ill inevitably be replacing (bearings, filament suppliers, etc).

Specifically to Gary, the only thing im unsure about with my build is the extruder head.  Id like to use Gregs Accesable wades with the herringbone gears, but im not entirely sure if it will mount on the platen without a adaptor.  Do you see this as being a issue?

I have seen the Gregs Accessable with Herringbone Gears extruder pre-printed on Create3d for $15, and ill grab that from them unless anyone is kind enough to print me up one.

[Garry Stone]

The only issue with using a standard extruder design on the ordbot is the amount of Z you lose by mounting it on the X gantry.  I have yet to mount my stilts and am unsure whether this will compromise the actual printing.  Installed as you saw mine you lose 40-50 mm of Z height.  If the qu-bd extruder had of been reliable this loss would have instantly dropped to 20mm, and given greater flexibility for dualextrusion.

 

On the electronics from reprapdiscount, he quite frequently has 10packs of each of his kits at a greatly reduced cost, if you could find 10 people to share the cost you could make a considerable saving here.

 

Garry

On Thursday, November 15, 2012 11:11:42 PM UTC+11, Nat Allan wrote:

[Nat Allan]

Dinesh, I picked up the ultimate kit from reprapdiscount last night.  This includes a V2A heat pad in the kit in the kit (along with both hall and micro switches, the board + shield  wiring, LCD and SDramps card)  That heat pad is for the Prusa model but its measurements would fit the ordbot fine from what i can see.  I sniped one of the regular auctions he runs on the ultimate kit, as they seem to go for around $170USD, whereas his buy it now kit is set at $199USD.  Not a massive saving but its nearly paid for my first roll of filament.  Reprapdiscount has added hall switches as part of the ultimate package which is good to be able to have the choice when it arrives, I guess lots of people were looking for them.

I have forgotten a PSU in my price.  Im still deciding how to go about that, as id prefer to have one small enough to have bolted to the machine and not have to carry it seperately.  I did see some people using xbox power supplies which would be a neat idea, but I think youd have to run a second adaptor just for the heat bed.  I have seen some slimline PSU's that were designed for lighting circuits I think that mount neat, but might be a little expensive.  Unfortunately I'm a bit of a neat freak when it comes to wiring and design, and it would be great with the SDRamps capability to be able to have it a plug and play affair with minimal parts hanging off it.

Did you get your whole extruder from extrude3d?  It looked like on the site he only offered the extra herringbone gears for the machine, not whole extruders.

Garry, I have looked at a lot of extruders and it seems like the non-geared designs just dont cut it as they dont seem to have the torque (i.e. qu-bd & makerbot Mk7).  A 'regular' geared extruder seems to be the only safe bet really.  I was thinking that you could design a solid mount raiser that you could bolt through all the way from the extruder, through the riser and into the X gantry, and possibly secure it to the back of the gantry too to ensure it doesnt move (at the expense of a heavier load on the gantry i guess).  Initially loosing some z-height wont frustrate me too much, but id like to gain that back at some point.

What made you choose hall effect switches over microswitches?  The biggest gain i can see would be ease of micro-adjusting the z-home location with the trimpot on the circuit.  Is there any other advantage over hall vs micro?

Is the extruder head kit from extrude3d OK?  Any recommendations on head size?  I was thinking 1.75 with a 0.40mm orifice would be the way to go to get started.

I had intended to attend this mondays meet but I have a interview first thing Tuesday so ill have to skip it.  Unfortunately I don't think ill be able to attend much until im a bit more setup after moving to melb.

[Garry Stone]

Good score on the electronics, great price, given whats in the kit.

 

the mk2 heated bed boltholes line up diectly with the ordbot Y plate.

I just bought a box of 4 mirror tiles from bunnings mirror section, they are quite thick, apparently ikea have some 200mm square mirrors that are thinner, then just buldog clipped the mirror to the heated bed.

 

Endstop switches, I went with halls effect as they seemed to be smaller, and with contactless action didnt require as accurate a mount.  I too initially thought I would be using the pot to adjust positioning of Z height, but now just leave the height alone, home Z to Z max, and use offset in slicer to adjust for small height differences.  To clarify the last part, I set my Z height to 152, and home to the top of my Z axis, the bot then goes to position 0 which I either adjust the bed to be at the right level, and if I think i need more or less squash on the plate with my first layer set Z offset in slicer to a positive or negative number.

 

No complaints here from the extrude3d hotend, it addresses a number of issues with the most of the other hotends of its type, Tom is very accesible and knowledgeable and keeps a stock of parts you will need at good prices and quick cheap postage.  The ptfe tube he uses is also pretty good stuff apparently.  Not much to compare the .4 to, probably would have gone .35, but that is what my qu-bd hotend is and when I asked Tom which I should chose other then .35 he suggested .4.

 

For the geared extruder I have already printed a set of "stilts" but am trying to think of a way to incorporate 2 printheads and extruders in a package that suits the hadron x gantry.  Am a bit curious why you are going 1.75mm, 3mm filament is generally cheaper and more plentiful, has a small advantage in the lesser torque required to drive it, but you are using the geared extruder which doesnt have this issue.  I went 1.75mm because I had signed up for the qu-bd extruder, and find the choice in 1.75mm filament a bit limiting.

 

Hope this helps somewhat

[Nat Allan]

Thanks for the info Garry.

I think the only bolts I haven't allowed for are the ones used to attach the heat pad to the y gantry with springs.  Are they a Bunnings job or better off sourcing from a decent engineering store?  Haven't really had to source proper nuts and bolts before.

As for the pick of hot end, its up in the air.  There's not a lot of objective info out there.  Also, the sites i saw around for buying filament were by the KG so I didn't see there being any price difference.

My thought's so far would have been:

3mm:           More cross section volume so requires slower drive.  Longer to heat through to centre.  More surface area for hobbed bolt to grab to.

1.75mm:       Inverse of above.

I had found a few people that felt 1.75mm was better for more detailed prints, and 3mm better for larger, higher volume prints.  Unfortunately i need to choose a happy medium as i plan on doing both type of printing.  If you redid your extruder would you go for 3mm?

Ive been thinking a bit about dualstrusion on a ordbot actually.  Have you considered a bowden cable method?  I think this would be the best way to go for the ord bot, as the direct drive extruder's just don't seem all that great performance wise.  I was thinking that down the track for me that might be a mod to work on, I see Tom's hotends can be adapted for it.  It has the benefit of moving a lot of the workload gear off the gantry, giving you more room to work with and lower mass on the gantry (Not that backlash seems to be a issue on the ordbot).

[Dinesh Kantheti]

Nat,

The current printer I have is with bowden extruder.  I have a no so great experience with it.  While it has the advantage of taking out some moving mass, the extrusion is not sensitive.  there is a lag in the PLA flow and extruder run.  I am bringing my printer to the hacker space tomorrow.  you have have look. Also happy for you to experiment.

Dinesh

[Dinesh Kantheti]

Hi Nat,

Did you make any further progress in procuring the frame etc.?

[Nat Allan]

Hi Dinesh,

I indeed have. As of yesterday i have the ordbot kit from ati, the ramps ultimate from reprapdiscount, assorted parts from bilbycnc (screw kit for a wades extruder, kaptom tape, extra fans, etc) and a 3mm 0.4dia hot end from extrude3d. Im only waiting on power supply, the printed wades extruder head, and some pla.

Ill be assembling the kit over the weekend, and hopefully ill have enough time to fuss with how i want the wiring to run, so that when the rest arrives next week ill be ready to run. Im really fussy when it comes to cabling!

I will most likely blog the build process like i usually do if your interested.