Yikes where do I start.. I hope I did not make a mistake

Hi All,
I am very new to 3D prinitng.. as a matter of fact I dont even have the printer yet.. its is flying to me as we speak.
I was doing some research into the different printers and really want to dabble into 3D printing but could not really afford any of the bigger ticket ready to go models. Although I am rather technical, I was a bit concerned about attempting to build one myself as I am a bit of a klutz and I am sure it would have ended in disaster.
So I went for the next best thing. I bought one of the preassembled mendels. I know there is lots of fiddling and adjusting to get them printing right and that part I don’t mind. However it never really occurred to me to check up on the supplier. In my case it’s a preassembled botmill printer I am buying from someone who never used it. I have read many negatives in regards to these kits.
Am I doomed? I notice the botmill forum has zero posts.. that’s not a good sign as I really want to collect as much info as I can since I am jumping into the deep end with a prebuilt one.

My first action will be to just delicately test out the movements manually at first with the printer off and then once hooked up do some manual tests of the drives without any filament loaded so I can check the axis all work, plate is level and head temp is somewhat accurate, etc. Is there a good site that covers starting up the printer for the first time?
Some of the horror stories are scary.

Bill D

Edited 1 time(s). Last edit at 02/09/2012 09:43PM by TechnoBill.

I haven't followed the Botmill saga, but I imagine that being "preassembled" you should be getting something with all the basic bits.
Which means you would be no worse off than someone like me who built my Prusa from the ground up...

So - doomed - probably not... (except to maybe lots of late nights tweaking extrusion parameters to perfection and honing OpenScad models to "tidy up that last little bit" - but that's not the machine's fault )

It's definitely a good thing to spend time prepping the mechanics before getting near any hot plastic. (I had to wait a couple of weeks for my first PLA - so by the time it arrived I had pretty good levelling and X/Y/Z calibration)
The botmill appears to be a form of the "Original Mendell" - you can find links on the front page of reprap.org, and the search function on this forum will turn up heaps of tips, on terms like "calibration".

And if you get stuck on any point - a quick query here usually gets answered PDQ.

Thanks.
Actually I am feeling more confident today. Because this is all new to me I went searching and of course all I could find is problems and that worried me a little. Of course more people tend to yell about complaints than virtues (not having a go a poeple that have reasons to yell, it's just the nature of forums).
The person from whom I bought the printer has been quite helpful. I think he has several and indicated he has had no problems with his. He also printed me a spool holder and some other things he says would come in handy which was real nice of him.

At first I though the one I was getting was a different model to the Glider as the gears on the Wade extruder were on the side rather than on the front as I see on their site. I guess they have changed it around a little at some point as I have seen both combinations on the various tubies.

The seller also sugested that I stick with the stock software for a while as it is calibrated for the printer. Only change things once I understand whats going on.

OK now I need to go looking for more safety tips.

TechnoBill

Firstly it pays to do your research, searching the forums or google for botmill brings up a lot of very unfavourable reviews, they are to be avoided at all costs!

[forums.reprap.org] - Anyone Have BotMill Feedback?
[forums.reprap.org] - BOTMILL is a NIGHTMARE
[forums.reprap.org] - Any BotMill joy yet ...?

3D Systems recently acquired Botmill, which is the reason that you're not going to have to wait 8 months to receive your printer, and the quality has been improved, though there are still some unhappy customers.
This is not me telling you that you have made a mistake, its preparing you for what might come. Fortunately any problem can usually be resolved. Self sourcing presents a whole host of problems that need resolving. The difference is when buying a kit that is advertised plug and play, you expect it to be plug and play.

Good luck, I hope it works out for you!

If the person your buying it from hasn't used it before ask them to ensure every part is there. Botmill had a habit of sending kits with missing parts or giving the buyer an iou and sending the part(s) later.

Luckily your buying it via a third party as a lot of the issues with Botmill as actually getting the product in the first place.

---

My Reprap blog

jds-reprap.blogspot.com

the implication from the original post was that this was not a purchase from Botmill, but "from someone who never used it.", (a cooperative seller by the sound of it)
so the delivery problems of "bought from source" botmills should not apply.

TechnoBill - a reassuring quote on the forums I recall from my early days (a whole 6 weeks ago when some things didn't seem to want to work right was "Don't give up, we can get everyone printing eventually"

Edited 1 time(s). Last edit at 02/10/2012 04:50AM by nb99.

nb99 Wrote:
-------------------------------------------------------
> the implication from the original post was that
> this was not a purchase from Botmill, but "from
> someone who never used it.", (a cooperative seller
> by the sound of it)
> so the delivery problems of "bought from source"
> botmills should not apply.

Ah yes I missed that, in that case you may have more luck

> TechnoBill - a reassuring quote on the forums I
> recall from my early days (a whole 6 weeks ago
> when some things didn't seem to want to work right
> was "Don't give up, we can get everyone printing
> eventually"

Indeed, get on IRC - there are over 300 members daily and a fair number of active members and developers who are willing to help!
[reprap.org]

If any problems arise there are dozens of sellers on there covering every component required for a full build.

Thanks,
Just confirming, I am buying through someone else who actually uses 3d printers for his small business, making mockups before getting real parts manufactured. He mentioned he has one of these already and is now using his experience to build his own bigger printer. This one is a second unit that he has but has not yet used. I assume he probably bought two at the same time to take advantage of the substantial savings and cover some of the costs of shipping to Australia, etc. I am fine with this and got this unit for less than the retail price including delivery, with some extra printed useful bits like a spool reel and clips, so no complaining there.
He believes it all looks correct and suggested I "carefully" tighten things up when it arrives, that was the only thing he noticed with his unit maybe as a result of the shipping some things were a little slack. After reading the original negatives I did ask if he could test it without plastic before sending it, but it was alread on its way.

I am not so worried now except I was hoping to be able to find more info on pre use checks and maybe the plans for the unit so I could print spare bits when I get it tuned.

This is very exciting'ish. IRC hmmm been a loooooong time since I used that.. I will look it up.

Thanks again.

Bill D

---

'Serenity' Observatory

[www.billd.net]

"Money frees you from doing things you dislike. Since I dislike doing nearly everything, money is handy."

Groucho Marx

As far as plans go - this is probably as good a place to start as anywhere..

Original Mendell construction

(again - this assumes the Botmill model you are getting is this version of Mendell - pics on the Botmill page certainly look like it.)

One of the links is to the "Mendel solid model files". If you haven't already, then get OpenScad (free 3D CAD, scripted rather than GUI - you'll learn to love it ! ) - as the files are in that format.

There are also assorted notes on checking the mechanical assembly.


I can't find any obvious single wiki item for "steps for first time you switch on", this was my approach..
There may well be better procedures out there somewhere - or provided with particular commercial products.
Also - these were my "starting point" - you will find plenty of advice on refining all of this from the experienced reprappers on the forums.


- use a small level and plumbob (e.g. nut on cotton) to check the horizontal and vertical bars are just that.
( and also the bed should be initially approximately levelled, before precise levelling below)

- the extruder rotates freely - (eccentricity in printed gears can cause tight spots)
- the bolt hobbing is lined up with the filament feed holes
- you can insert a piece of filament and wind it through manually, and the hobbed bolt grips well,

- the X & Y belts should be firm ( supposedly taut enough so that when tweaked should hum at about 100hz)
- ensure the travel on the 3 axes does not foul anything, and doesn't have "tight spots" (lightly lubricate smooth rods)
- the limit switches are positioned ok
(if micro-switches, they click before the bed Y movement or X carriage run into the framework, or Z runs into the bed,
if optical, then the flags seat correctly in the opto-sensors (see note below) )

After the endstop checks, you will have found winding Z up and down by hand is fairly tedious.
At this point I center the X carriage & the Y bed, raise Z a few cm, and apply power.
Make sure the power switch is readily accessibly just in case anything odd happens.
The usual power supplies found in repraps (often ATX PC PSUs) will shut themselves down if there is something serious like a short.
Optionally measure the 12v supply - if it's around 12v, then there's no major problem yet.

With the printer connected to your PC by USB then the host s/w should now be able to communicate with the firmware on the printer.
There will be a manual movement control panel on the PC S/W. They pretty much all have similar functions.
Select +10mm on X. Ensure the X-carriage moves to the right.
Same on Y, the bed should move away from the endstop.
For Z - it should move up.
If any of these are reversed, either reverse the wiring to the relevant stepper, or, usually easier (for some) edit the firmware, locate the relevant axis INVERT definition, alter, recompile, reload firmware to printer.

ALWAYS TURN POWER OFF BEFORE TOUCHING STEPPER ELECTRICAL CONNECTORS - inductive spikes kill stepper drivers. Expensive.

Test Homing. If there was to be a problem with the Home end-stop detection, it's too late to find out when the carriage or bed hits the stop and tries to keep going. So I "fake" an end-stop hit well before then.
Either put your finger near the end-stop microswitch, or hold a piece of card or similar (opaque) close to the opto-sensor - (having practiced inserting it)
Now hit the Home-X control. The carriage should start moving towards the end-stop. Fairly quickly press the end-stop micro-switch, or insert the card into the opto-sensor slot.
The carriage should stop, and will usually "bounce", i.e. it reverses away from the stop position a few mm, then retries. (I think this is to counteract any error due to a possibly higher initial "home-seek" speed. )
Be prepared to hit the power switch if it ignores the activated end-stop - because it is likely to just keep going and try to step right through the frame. (in fact, apart from some belt and pulley stress, it is not catastrophic for a stepper to hit the wall for a short time. It just grumbles loudly. )

Do the same with Y.
If they acknowledge the end-stops correctly, it should be safe to try the X & Y home controls for real.

Z is another kettle of fish.

- initial Bed level check: ( you first need to determine how your bed height adjustments are made. Often a screw at each corner.)
If the bed has not been precisely levelled before, e.g. if you have opto end-stops and this is the first "power-on Z-home",
you don't want to take the extruder tip all the way down to Z-home under power before ensuring there will be positive clearance. Negative clearance is a bad thing. The extruder is likely to be damaged by being driven into the bed. This will be less so if the bed is sprung.

With X & Y at the home positions, use the control panel to move Z down until the extruder tip is a few mm from the bed.
Then *while observing the tip clearance* gradually drive Z down to 1mm then in 0.1mm steps until the end-stop switch clicks or the opto flag enters the opto-sensor. The firmware *should* refuse to drive another 0.1mm once the end-stop activates.

If the tip gets less than 0.2mm from the bed before the endstop kicks in,
then you need to either take the endstop up some, or adjust the opto flag down
or use the bed adjustment to lower that.
You are aiming for about 0.2mm clearance between tip and bed when the Z end-stop activates. (actually about 0.1mm less than your intended print layer height, I use 0.3mm)
You need a Clearance Gauge - I just use a folded piece of copy paper. Two thicknesses is fairly accurately 0.2mm, and should just slide under the tip. Three thicknesses should not. (you do of course have that core reprapper's tool, a digital caliper? (from jaycar for us Australasians)
Once you have that clearance at X/Y home, then you must go round the periphery of the bed.
Take the Z-axis up until the smooth part of a drill bit neatly fits (rolls) between the extruder tip and bed at the X/Y home position.
( arbitrary drill size e.g. 3mm - a handy reliable size guauge, at this stage it's just to ensure there is the same level round the bed, at a safe enough height to avoid scrapes if there is a signifcant level difference first time round)
I then move X & Y round the corners of a rectangle a couple of cm in from each edge, and adjust the bed corners to get the same 3mm clearance.
You should go round twice - as each corner adjusted affects the others slightly.
Finally you can repeat the careful 0.1mm-at-a-time step check of full Z-home at X/Y home, and then run round the corners getting the same.

You need to check that levelling after any significant mechanical work - like removing and replacing the hot-end, or even an energetic digging off of a printed object well stuck to the bed. Possibly also after after a filament jam where you have had to put pressure on the extruder to get filament out, or pressed down to get flowing again.



( Opto endstops note: You can't tell when an opto has activated unless it has power applied. You could apply power, without actually commanding any stepper motion, put a meter on an end-stop, note how the voltage varies when you put a card in the sensor.
Look for the same indication on the meter when manually running the axis to its end-stop. )


For steps/mm calibration - see forum topics e.g. How to calibrate a reprap
Synopsis. Home an axis. command it to drive +10mm. Use digital caliper to measure distance of carriage or bed from a fixed piece of frame, both before and after. If the difference is more than a few % from 10mm, modify the relevant axis steps per mm in the firmware. This will be either dynamically settable from the PC S/W into firmware EEPROM storage, or more primitively will require recompilation of the firmware with altered source constant definitions. (If you have to do the latter, consider switching to a more modern firmware)
Once this gets close for a 10mm test, do a 100mm test. (The reason for not going straight to a 100mm test: if the value is badly out, you may be trying to drive off the end of the rods.)
With no hot-end in place, check a 100mm feed through the extruder.

Thats Fantastic info, thanks. I will follow it the best I can and take my time (rare for me).
From what I have seen in the images when I bought the printer, its a typical mendel with a wades extruder and it uses a Gen6 board.
(hehe makes it almost sound like I know stuff)

Regards
Bill D

Well the preassembled printer arrived today. Generally I am very happy with the quality of the components. However the build was a little mucked up even to my newbie eyes. To be fair this printer was actually purchased about 4 months ago and only just opened now. So its before the new guys really started trying to pick up the pieces and turn things around.

The issues I had except one were all relatively minor I think:
* Blank USB stick.. so much for precalibarated and configured software :-)
* Some loose bolts to be expected.
* Wiring location for Y axis badly placed. Came straight down from board to sensor so when plate moves back it hits the wiring and dislodges the sensor. I Re-ran wiring along outside and along bottom.
* A nut missing on the head. They must do a nut count because the extra nut was sitting on the end of an existing bolt on the frame. I guess when they could not work out where it belonged they put it there. Thats fine with me, better than a missing one.
* head carraige very sloppy on mount but that was just a few more things to tighten
* Threaded rods for Z axiz extended well below bottom of the machine so I had a rocking horse. I imagine it would have crawled across the table if I powered it up :-). I will add some rubber feet.
All of the above were correctable. This next one worries me a little and I wont know until I power it up:
The Gen6 board was bolted to a perspex plate quite tightly without any standoffs so it was bending due to the pins and solder that stick out the back of the board resting on the perspex and the bolts in the corners being tightened and pulluing the corners in. I removed board from printer and added some stand offs. Hopefully its initial attachment and bending did not crack any tracks. The printer does have plastic fillament in the extruder so if they tested it in this configuraton, I am hopfull its all working.

So tomorrow I just have to level the plate which is OK in x but out slightly in Y. follow some of the great instructions in the previous post and I think I am ready for power up.

Bill D

Edited 1 time(s). Last edit at 02/13/2012 08:04AM by TechnoBill.

---

'Serenity' Observatory

[www.billd.net]

"Money frees you from doing things you dislike. Since I dislike doing nearly everything, money is handy."

Groucho Marx

Well I just though I would update those that might be intested.
I know have my BotMill Glide printer working reliably and I am really happy with the print quality.
Its been a bit of an effort and would not have succeeded without the help of the good peeps on the #reprap IRC.
It is basically the standard printer as supplied by BotMill with the exception of the hot end that fell apart on day one and the Hobbed bolt (replaced it with one that had a groove in it as it seems to guide the filament better. Currently I am using the J-head MarkIV-B hotend.

Just used to to print my first improvment witch is a more eailly adjustable Z Stop. Its a bit hard to make out with the black PLA but it Works!!!!

[www.flickr.com]

Bill D

---

'Serenity' Observatory

[www.billd.net]

"Money frees you from doing things you dislike. Since I dislike doing nearly everything, money is handy."

Groucho Marx