In the process of printing PETG I had many failed prints, prints would suddenly stop and reset itself, the extruder would suddenly get stuck, stepper motor skipping steps causing alignment issues. I think I lost 250g worth of plastics because of this.



I couldn't understand why because the PLA printed just fine. Spend 5 days troubleshooting and then I thought perhaps the stepper motor driver is overheating because of the extra power from the heated bed and extruder heater block. While trying to touch the stepper motor driver my finger accidentally touched the polyfuse and I realise they were burning hot. My guess around 60c, similar to my PLA heated bed temp.
But fuses are not meant to be hot.

Went around finding the part number for the RAMPS board polyfuse and found 11A polyfuse and 5A polyfuse rated. Immediately I knew this was a bad design, who in the right mind puts in 11A of fuse rating when the bed is around 1ohm and 12V rated which is 12A at normal load. Even at normal usage, the bed can draw up to 13A. The issue was the same for the 5A polyfuse. The fuse also doesn't take into account derating at high temperature.
Also the way polyfuse works is they need high current to trip and if your draw current is neither low enough to keep the polyfuse cool or high enough to trip the fuse, you get into an intermittent stage where your polyfuse acts semi high resistance which burns a lot of power.

I knew that I couldn't be the only one facing this issue, I'm pretty sure someone else also pushed the heated bed and extruder heater near the limit should also face the exact same issue as I have.

True enough, it was a well known issue:-

https://www.reddit.com/r/Reprap/comments/2q...n_seconds_do_i/
http://forums.reprap.org/read.php?219,458481,488483



Some even suggested removing the polyfuse and replace it with a short.
http://rigidtalk.com/wiki/index.php?title=...RAMPS_1.4_board

So after soldering a wire across the fuse to short it I no longer have these issues. Just to share.

Have you done your Z axis yet?

Not yet finish. All the frame , z axis, limit switch done pending extruder section now. I notice my z bed design which is similar to ultimaker 2 is a little bit springy, so i was wondering how is your design like ? 1 lead screw , two rods or two rods and two lead screw?


Will post a video soon

Z axis and Limit switches done. One more extruder carriage and will be able to print the first print.





The cantilevered bed platform is slightly springy at the end. Will see whether I need to add more lead screw at both sides to keep it solid. I wonder if the ultimaker2 has the same problem.

On the side note , the combination of linear rails, motor dampers, and the DRV8835 really makes the whole setup quiet. The fan noise and even the limit switch clicking sound is noiser than the stepper motors.
The Z axis integrated leadcrew/stepper motor really ensures that the lead screw stays exactly 90 degrees/ 0 wobble and very very smooth compared to my prusa.


This post has been edited by Drian: Apr 18 2016, 10:07 AM

Yup it's a nema 17 motor holder. I used this because it is extremely stiff, and I wasn't comfortable with using plastic L bracket for the cantilevered bed.

Will see how the first print goes and see whether I need to add two more lead screw to support the ends


This post has been edited by Drian: Apr 19 2016, 12:19 PM

It seems like Ultimaker is also having this issue

something for you to think about when you do your z axis.

From the forums it seems to be an issue if you print big parts that uses up the bed all the way to the edge.

https://ultimaker.com/en/community/15881-of...imaker-original
https://ultimaker.com/en/community/20125-fi...bed-oscillation
https://ultimaker.com/en/community/8869-um2...destruct-solved
https://ultimaker.com/en/community/11184-fr...ildplate-shakes







This post has been edited by Drian: Apr 20 2016, 12:00 PM

That is a roll in t-nut that comes with a spring ball at the bottom. Because of that spring it is more expensive than regular t nut. But the lelong one is still expensive though.

Proper way to do assembly.
Not like me , figure out all the part clearance mentally only.

want to share shipping cost? I want to replenish all my tnuts, running low.

For some reason, tnuts are so expensive and rare in Malaysia. Screws and bolts are very easy to find, but when it comes to tnuts , none of them carry it.

You have heated bed springs?

ok no prob

Ok I will need to print some stuff in ABS for my heated bed.
Will send you the STLs once I'm done with everything.

why can't you plug and unplug again to reinstall the driver?

First Print




Now need to fix some minor Z banding issue and find out the appropriate acceleration and jerk settings.

weird they have a 25.4 which is a 1 inch X 1 inch or 1010 aluminium in US. They're exporting it to US?
However I think 2020 hardware might work on the 25.4X25.4mm. The Tnut gap dimensions are only slightly bigger than the normal 2020..

I think it was 120mm/s. It was already slightly underextruding at the infill , the hobbed filament gear wasn't really good and begin to grind the filament. Probably need to look at thingiverse for some good bowden setup with a hobbed filament gear.

Progress is slow, trying to perfect the hardware, I've made 3 iteration, first it was direct drive, but it was taking up so much space that I was losing quite a bit of travel length. Then I tried to come up with some ways that the setup could be more space efficient with the direct drive method but wasn't really successful. So I went for a bowden setup at the end. Will try to make the gantry smaller after this so that it is more compact.

Yup PETG is good, I'm surprise the adoption isn't any faster, so much easier to work with, and don't really like the idea of breathing toxic fumes from printing ABS.

Hello, it's been long since I'm here.

Since I've completed my CoreXY printer project, my prusa aluminium printer is now collecting dust.

Anyone who wants to buy it, I'm selling it real cheap. The only thing is you have to print out the plastics for the printer again as the PLA will become brittle after some time(preferably convert to ABS or PETG).
This design uses Aluminum so it's more sturdy and rigid compared to the all plastic design.

The Prusa I3 is based on blomkers

http://reprap.org/wiki/Prusa_i3_Blomker

All the instructions are clearly laid out here.

PM me if interested.

Wow on filament making, you're getting plastic pellets and making them into filament?

Now I'm starting on making my own Delta printer.
300mm diameter bed based on the kossel XL design. Planning to house it in an ikea enclosure.

Planning to use high end components (magnetic ball joints and Force bed probing) to give it a more industrial reliability.
Using Duet Wifi 32 bit controller as the host.

My benchmark is my company's stratasys fortus machine.

If you want to really check the layer quality and alignment, you have to use dark colour under light. White and light colours hide imperfections.