[RobertKuhlmann]

By the way: I made very good progresses in merging the armlevel- and the Yogi-branch, together with new-mathematics.
I’m confident to get ready before this weekend (and tomorrow we have a holiday here).

I’m done with
cardreader.cpp cardreader.h Configuration.h Configuration_adv.h ConfigurationStore.cpp ConfigurationStore.h fastio.h language.h LiquidCrystalRus.cpp LiquidCrystalRus.h Marlin.h Marlin_main.cpp MarlinSerial.cpp MarlinSerial.h motion_control.cpp motion_control.h
so far, working on “pins.h” which is a lot of work because of several new boards, that are defined in there.

With the result it should be very easy to keep Morgan’s Marlin up to date with recent Marlin improvements.
If we are successful with this, the new trigonometrical functions might make it into the official Marlin too.

Merging is a good practice for me to get deeper into the Marlin-code and to understand it.

[RobertKuhlmann]

Great.

And one further suggestion:
We should combine both ways. Yogi’s auto-leveling and your armlevel and make it selectable with a symbolic constant.

Homing to z=0 or z=max should be selectable with a symbolic constant too.

And I will learn how to use Github for collaboration…

[RobertKuhlmann]

Here’s the complete Marin-armlevel with new_mathematics. It compiles without errors now but is untested:

http://reprap.org/wiki/File:Marlin_armlevel_new_mathematics_beta.zip

That’s all for today. Have to go to bed now.

Bye
Robert

[RobertKuhlmann]

I’m compiling now and correct some errors. Will send you an update soon.

[RobertKuhlmann]

Very good. I’ll do my part and try to transfer the sqrt-assembler code within the next days.
If accuracy becomes a problem, we could try to use larger tables, maybe up to ten times should be possible.

[RobertKuhlmann]

I’ve invested some time to transfer the idea to Marlin.

Here are three files, that we can start with:
http://reprap.org/wiki/File:Marlin_mathematics.zip

math_tables.h – holds all conversion-tables for sin, cos, tan, acos

new_mathematic.h and .cpp – new fast functions fsin, fcos, ftan, facos, fatan2 (fsqrt as a dummy)

Oscar Liang obviously used deg-parameters, while Arduino wants rad. So I had to change a few things and I prepared the value-tables, not included in his blog.

I did include the assembler code for fsqrt as a comment but didn’t work on that now.

TODO:
1. fsqrt
2. Exchange trigonometric calls throughout Marlin (no big deal with Visual Studio though).

If someone wants to help me finish this work (e.g. test accuracy or impact on printing a.s.o), you’re welcome.

Greetings
Robert

[RobertKuhlmann]

How about using this library:
http://blog.oscarliang.net/enhanced-arduino-c-custom-math-library/

He only missed to optimize sqrt – damn.
But maybe we can complete Oscar’s library with the approach shown over here:
http://www-user.tu-chemnitz.de/~heha/Mikrocontroller/Wurzel.htm

The “manual way” is implemented in ATmega8 there already. I didn’t dig into that too deep now but it should be possible to enhance it for our needs.
Maybe even the “reference-table”-approach would do the job, but I didn’t check the table size we’d need for that. But the manual way should be good enough.

[RobertKuhlmann]

Here come the promised pictures of the heating wire for the big building platform:

http://reprap.org/wiki/File:Bed_of_nails_for_heating_wire.JPG

http://reprap.org/wiki/File:RepRap_Morgan_big_platform_heat-wire_resistance.JPG

http://reprap.org/wiki/File:RepRap_Morgan_heating_wire_fixed_to_platform.JPG

[RobertKuhlmann]

Good news.
The big building platform performs very well. An insulated copper wire with 0,56 mm diameter copper, 0.62 mm total diameter and a length of app. 41 m, divided in two halfs of 20.5m each (connected in parallel), giving a complete-resistance of app. 1.1 Ohm heats up from 21° C to 60° C in less than 6 minutes, using 10.9 A at 12 V/DC, consuming app. 130 Watts.
The wire was formed on my bed of nails, that I made for this purpose and then fixed to the platform with capton-tape. (will post photos tomorrow)

The heating up time is measured without any isolation underneath the platform. I think it would heat up much faster, if I place a heat reflector under it.

I have fixed the hotend (gave it a bigger heater barrel and a new thermistor) and it performs very good now. I used a stripe of capton-tape to limit the fan’s air flow to the cooler and prevent it from cooling the heated end.

I also had to fix my extruder, changing its stepper and fine tune its montage.

Last show stopper was my z-axis (a trapezoid rod). The firmware seems not to be prepared to use different feed-rates for XY- and Z-axis. I had to reduce the maximum feed-rate to the value, my Z-axis accepts.

Prior to finish my first successful print on my Morgan I’ll have to do another z-axis-calibration and to prepare the aluminum-surface of the big building platform for holding the freshly deposited ABS (hairspray, sandpaper, Capton, whatever).

Still waiting for my Pico hotend though an some new parts for tests with a threadless ball screw for the z-axis, as well as Quentin’s Alpen drill solution.

The Morgan being my first 3D-printer told me countless lessons. I wish I’d have started to build a “spare” printer more early, to be able to print the parts needed myself. But my time for this project was and is limited.

[RobertKuhlmann]

Hello Quentin,

my big bed is heated of course. I made a bed of nails and created a copper-wire-mesh with it. But I have to modify the wiring, because I need more power to heat it up more quickly. And I will give Pyralux a try (Pyralux is Kapton with a copper layer on it – can be etched like a PCB). Pyralux may be an option for standard heated building platforms as well. I’ll receive several examples for testing in the next days.

I’m using a modified toolhead anyway (with integrated fan) and will place the new hotend in the optimum position.
That one can be used to print even with PC at above 300° C, but needs a different thermistor for that. But I’ll try ABS and PLA first. I’ve modified my existing hotend meanwhile, because I’m still waiting for the new hotend to arrive.

[RobertKuhlmann]

Still waiting for my new Hotend:

[RobertKuhlmann]

I had the same problems at first.
Having a similar setup to your Morgan, I’m using the following entries in Configuration.h at the moment:

#define DEFAULT_AXIS_STEPS_PER_UNIT {211.18, 211.18, 2129.83, 100}
#define DEFAULT_MAX_FEEDRATE {5000, 5000, 11, 100}
#define DEFAULT_MAX_ACCELERATION {9000,9000,9000,500} // X, Y, Z, E maximum start speed for accelerated moves.

You may use the commands instead (extruder not calibrated yet):
M92 X211.18, Y211.18, 2129.83, 100
M203 X5000, Y5000, 11, 100

You have to take into account, that I’m using a trapezoid threaded rod as Z-axis, not Quentin’s “alpen-drill-solution”. So my Z-values will not work good with your build.
“211.18” is calibrated of course. You should begin with “215” for X and Y.

[RobertKuhlmann]

It doesn’t seem to get hot enough and loses its working temperature very soon (even without using the fan). I’ll give it a try with a bigger heater barrel I’ve ordered a different hotend as well:
It’s small and lightweight. Looks promising to me.

The Morgan’s arms are relatively high above the top platform, so I’m able to use several kinds of hotends.
I can adjust the height of the building platform in a range of several centimeters.

[RobertKuhlmann]

Here are the pictures (2nd try):

[RobertKuhlmann]

Hm. No images?

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