Built MendelMax 1.5, calibrated axes, leveled bed, what next?

Hey folks,

I'd like to ask for a bit of help figuring out what the next step is in setting up my MendelMax 1.5. I've build the printer, verified everything is square, leveled the bed (using a folded piece of 24lb copy paper), and calibrated the x, y, and z-axes using calipers. The endstops work and are set. I haven't touched the extruder yet and don't know how to calibrate it. I'm thinking that one of the next steps would be to print a calibration cube, but am somewhat stuck on what steps I need to to take to get there. I'm using the Marlin firmware and Pronterface.

Can someone please provide a bit of guidance? Many tutorials exist to build the MendelMax, but I'm having difficulty finding a succinct guide that follows through with calibration, software, and an initial print.

Thanks!

Edited 2 time(s). Last edit at 05/06/2013 11:56PM by Zangetsu57.

next step will be to test your hot end see if it heats up and the temp readings are normal

In pronterface look bottom left and set to 185 (PLA) then press set . Press check temp and "watch" so the active graph works. You should see your temp rise then remain stable at 185.
Raise z axis by 10mm or so from your build platform
The put some filament in the extuder and try to extude ( Extude 5 mm to start with)

Then you can try calibrating the E steps for your extuder

Good luck

Do I need to calibrate the thermistor for my heatbed and extruder? I think they are 100k, but I don't know what brand.

On another note, I'm using the "Universal Y-Plate" featured here: [mendelmax.terawattindustries.com]. My heated bed takes a little while to heat up. The power supply is rock solid at 12V and is rated for 20A, so I doubt that is an issue. I think the problem is the current design has no insulation so heat is lost on the bottom half. Does anyone have any ideas to get it to heat up faster and maintain a 100C temperature?

Edited 1 time(s). Last edit at 05/07/2013 03:06AM by Zangetsu57.

There's nothing to calibrate on the thermistor. Just needs identifying (correctly) in your config.h file

The only thing i do with my heated bed is i have a layer of kapton tape under my heated bed . Certainly covering the temp sensor. I live in Asia where i often have the air con running so don't want cool drafts effecting the temp sensor performance. Minimal chance but for the sake of a 2 cent piece of tape its worth it.
Once your sure you have both the extuder and heated bed working You might try the autotune PID option in Marlin
see this blog lincomatics blog as its worth a read

Good luck

After you make sure the hotbed and bed heats up you will have to calibrate the extruder

Did you set Marlin up to match your particular printer design?
Steps per mm need set for all axis to match your lead screws and belts and pulleys.
Endstops set correctly ?
Feed direction?
Board type etc....

Can I calibrate the extruder with the hotend installed? Also, roughly how much tension should I apply between the bearing and hobbed bolt via screws? I'm worried that my screws are a bit short and I might need to buy some longer ones given the springs I have :\.

may depend on a few things like spring type and strength.
In theory the less tension the better as it reduces the chance of the hobbed bolt chewing the filament. But of coure you need enough tension to ensure the filament does slip
Some say finger tight .some say finger tight plus 2 full turns

Its a trial an error thing . Youll soon figure it out . Id say start with as tight as you can with your fingers ...as a start

Good luck

Zangetsu57 Wrote:
-------------------------------------------------------
> Can I calibrate the extruder with the hotend
> installed? Also, roughly how much tension should
> I apply between the bearing and hobbed bolt via
> screws? I'm worried that my screws are a bit
> short and I might need to buy some longer ones
> given the springs I have :\.


Yes you can, just heat up the hotend to the right temp, 230 for abs and mark 20-100mm of filament, then tell Repetier or Protoface to extrude that much (as marked) then measure if line is still visible, if not then extruding too much.

If I command the extruder to extrude 10mm, should it feed 10mm of filament into the hotend, or extrude 10mm out of the nozzle?

10 mm into the extruder

Thanks Spk. I thought so, but wanted to be certain.

What is a good speed to set the extruder to when calibrating? I intially used 300mm/min but the length of filament fed into the extruder was inconsistent (perhaps due to inability to heat up filament fast enough or skipping on the hobbed bolt), so I backed it down to 100mm/min.

Edited 1 time(s). Last edit at 05/10/2013 06:54PM by Zangetsu57.

20-30mm is plenty fast for calibrating, you want it to go slow so no slipping takes place.

Alright, I managed to calibrate the extruder. Thanks everyone!

Question: should I set the endstops physically where I want the home position to be? The range of linear motion along the x and y axes extends past the print bed by a bit on each side. Ultimately I want to restrict the print area to the bed, keeping the head a few mm away from the binder clips keeping the glass attached to the MK2a heatbed. I'm using Repetier Host, if that matters.

Thanks for any guidance!

You could just add offsets and set the bed size to restrict it in the software.
I am guessing that the end stops are only being read while homing. So if you do hit and end stop while printing the printer will not stop.

Personally I just keep in mind where the clips and such are. Majority of the time I am never near them. Starting gcode brings it close on each print to purge the nozzle.

I'm getting closer to my first print, but have run into a few more issues:

1. I've been able to print the first layer on my heated bed, but all subsequent layers don't stack up. The hotend extrudes plastic but it doesn't seem to stick to the right layer; it appears too "stringy". Does this mean the temperature is not hot enough? I'm using 3mm ABS filament from [ic3dprinters.com]. Note that when I manually extrude an amount, it is almost immediately solid after exiting the hotend.

2. The hotend (J-head) is directly mounted to my Greg Wade Reloaded Extruder from Techpaladin via M3 screws. The extruder is full PLA. I notice that when the extruder is hot, it can "wiggle", but this doesn't happen when it is cold. I can only imagine that the PLA is softening due to high temperature. What is a solution to fix this? Use some sort of mounting bracket for insulation? EDIT: I'm thinking of this: [www.hotends.com]. Since aluminum conducts heat well, however, would this be an issue if mounting to a PLA extruder?

3. My heatbed struggles to reach 100C. I've thought about putting kapton tape on the bottom, but would such a thin layer of kapton actually help?

Thanks!

Edited 1 time(s). Last edit at 05/12/2013 05:06PM by Zangetsu57.

1. Sounds like it might not be hot enough. What temp are you running?
2. A PLA extruder will be a problem printing ABS without some active cooling to prevent it from getting soft.
3. Do you have the underside insulated at all? I used a single piece of cardboard wrapped in aluminum foil to help direct heat upward. To speed up heating of the plate I will place a piece of cardboard on top the plate. Once temp is reached I remove and print.

Spk64 Wrote:
-------------------------------------------------------
> 1. Sounds like it might not be hot enough. What
> temp are you running?
> 2. A PLA extruder will be a problem printing ABS
> without some active cooling to prevent it from
> getting soft.
> 3. Do you have the underside insulated at all? I
> used a single piece of cardboard wrapped in
> aluminum foil to help direct heat upward. To
> speed up heating of the plate I will place a piece
> of cardboard on top the plate. Once temp is
> reached I remove and print.

Hello Spk64,

Responses below:
1. 220C. Things seem better at 240C, but I can't really print yet due to the problem in (2).
2. Do you think I still need active cooling if I use that aluminum mounting plate? If so, would a 60mm fan zip-tied somehow to the extruder work, at least until I can print something better?
3. I don't, but these are good suggestions. I'll look into doing something like that.

I generally print abs at 230c so you may be a little cool depending on how your hot end is calibrated.
Cooling on the extruder might help get you printing but I would recommend printing an ABS extruder as soon as possible.

Are you using a standard j- head?
Any pics of your setup?

I've decided to move to PLA for the time being, at least to get started.

I purchased the aluminum j-head mount from hotends.com. The fit is pretty secure but I'm afraid that the hotend will move in the aluminum mount once heated up. Should I somehow secure it further to the aluminum mount (e.g. A little bit of CA glue)?

Thanks!

Edited 1 time(s). Last edit at 05/19/2013 05:35PM by Zangetsu57.

It turns out that the hotend does have a bit of wiggle once heated. Any ideas to keep it secured in the mount?

On an unrelated note, I've noted that in Repetier Host (and PronterFace for that matter), the y-axis prints are flipped (mirrored) compared to the picture on the 3D preview. I currently have my printer set up such that when the positive y-axis button is clicked, the bed moves away, and when negative is clicked, the bed moves towards the front (where I have the y-axis motor mounted). This forms a right-hand system so z is positive. Do I need to make changes in the Marlin firmware, or is there a way to have Repetier Host flip the y-axis?

Thanks!

Edited 1 time(s). Last edit at 05/26/2013 12:15AM by Zangetsu57.

Changing it in the Marlin firmware is where you should make the change. It may take a couple changes depending on where your y end stop is located.
My end stops are on the same end as the motor.