Chinese eBay 3D printer - Story so far, and request for advice

Hi all,

I had recently been looking at 3D printing as a new hobby, and following some initial research (arguably perhaps not enough), and the relatively low cost, I chose the the following from a supplier in the UK.

2016 Upgraded Full Quality High Precision Reprap Prusa i3 DIY 3d Printer

Supplier - printchainstore



The delivery was efficient, 3 days, so no complaints there.

First let me say that I am new to this hobby, so if I use the wrong terminology, forgive me as this is a fairly steep learning curve and any comments or advice will be appreciated.

I have had the following challenges so far:

Frame Parts
Whilst working through the parts supplied, I discovered that there were 2 right sides of the frame. Contacted the supplier, who advised they would send a replacement part from the UK. A week later, and no delivery, I sent a followup email and received a reply offering a £15 refund? I decided to take another look at the sides and discovered they were pretty much identical apart from the mounting holes for the power supply, and the hole for the power switch.

Solution: Modify the existing side and take the refund.

Broken Glass
This was badly protected and had been shattered during transport. Supplier notified and a £10 refund offered.

Solution: Take refund and source replacement.

Threaded Rod
As been previously reported in other reports, these were both bent.

Solution: Replacements purchased.

Temperature Readings
I was getting ready for the first test print, levelling the bed etc, when I noticed the temperature being displayed on the LCD panel for both the heated bed and the extrusion nozzle, were both reading 38 degrees, which was rather higher than the current room temperature of 23 degrees. This was confirmed with a temperature reading multimeter, and upon checking, the thermistor resistance was reading 50kohms. Contacted the supplier again, offered to send replacements but given their history, decided not to accept as Thermistors are relatively inexpensive.

I decided to go ahead and see if the filament would extrude, however upon trying, and after the first few millimetres, the motor started to ‘click’ and the filament stopped moving. I suspected the temperature was not high enough to melt the plastic, or so I thought.

Solution: Source and fit replacement Thermistors.

Extruder
Thermistors now replaced and correct temperature being displayed, time for the first test print, if only. I experienced the same problem again with regard to extruding the plastic, the temperature was now confirmed as being correct, so once cooled down, I disassembled the Extruder assembly and found the following. I believe this is a MK8 Extruder









I am no expert, but I believe this is supposed to be a hollow tube? Not being a magician by trade, this is another showstopper. Following more research, I understand this to be the ‘Hot End Throat’, and steers the filament to the hot end. This part does have a teflon tube inside, and is hollow most of the way through, just seems like the top has not been machined off.
I spent an hour or so last night identifying this part, and looking for a replacement. There are several offered on eBay, all China and Hong Kong, so I would have to wait several weeks for a replacement.

I’d appreciate some advise on this, and corrected if I am missing something.

I see a few options, await the part, replace the Hot End assembly, or maybe power up the bench grinder and try and ‘fix’ the current hot end throat by grinding the top off.

Would I buy another one? At the moment, probably yes, despite the ongoing issues. If nothing else, it’s a fantastic learning experience, and hope that perseverance will pay in the end. The knowledge and experience offered by this forums members is invaluable.

If you accept that there is likely to be minimal support from the supplier, and you may have to replace parts with better quality equipment, you are comfortable dealing with the problems, and the frustrations that ensue, then why not as these ‘kits’ look better value (even with replacing parts), than sourcing the parts independently.

I’ll follow up with the supplier on the latest issue, although I’ll not expect too much.

Brian

Quick update, I believe I have found a replacement 'throat' tube on Amazon, and will be here tomorrow, so fingers crossed.

I'll update on the progress, but feel free to offer any additional pearls of wisdom.

Thanks

Brian

Looks like some filament was left in the extruder. You can use a small torch or heatgun to melt it out. These printers are made cheap, but they will work just fine once everything is tuned up. It took me a few days to get mine up and running, and I had to redo my extruder and hotend. I would get some kapton tape and re-apply it to the hotend, also make sure the thermister is inside the block nice and snug.

Hi broy5, I wish it were that simple, it is solid metal.

I have plans to possibly replace the extruder setup, but wanted to see the printed quality first for comparison.
The thermistor is currently reading the correct temperature, and I will monitor that.

Appreciate the comments

I bought a similar kit, was a huge learning experience,
Also I had a similar problem with the filament clogging in the hot end, taking it off and putting a torch to it did the trick until I got a nice hot wnd

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If you need some help, or don't understand what I just said, feel free to send me a PM anytime

Printer: Prusa i3, 2 E3D v6 Hotends, Arduino + RAMPS 1.4 with a Bypassed 5V Regulator, 400w Insignia ATX PSU, Custom Designed Bowden Extruders

What does the other end of the tube look like? The end you are showing just looks like you could break it off and drill it out at the worst case.

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Newbie with Folgertech 2020 i3.

this is not an MK8 extruder as the throat on MK8 is fully threaded with teflon tube visible at both ends there should also be a brass nozzle. If you want replacement parts for an MK8 lookup RobotShop web site under tools and accessories 3d printer parts they also offer a complete true MK8 should you even want one or upgrade to an E3. I wonder if you could get enough refunds to build another printer. A lot of times they just stick the thermistor in the little hole and wrap it with the gold Kapton hoping it makes good thermal contact. I found coating the thermistor with high temp silicone and securing it in the aluminum block with same gave me better temp readings. The heater I coated in heat sink grease and made sure it was tight in the block. I find the MK8 works for me for now as I only use PLA and PETG it is ok for ABS don't even attempt nylon with it. If you upgrade the hot end make sure it matches your filament diameter and unless you go Bowden you need direct drive. For good advise also check out Toms Guides on YouTube videos.

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rwt

Hi Mseager, most of the tube is hollow, Just the last couple of mm that is covered. If I could not source a replacement quickly, the plan was to grind the end down.

I should have the replacement today.


Hi Roger123D
Thanks for the tips on the Thermsitor, you are correct that it is just shoved in the hole. I did have to replace it, so I’ll pick up some high temperature silicone and finish the job.

If all goes well, I should be able to attempt a print later today, I guess that’ll be the start of the next round of tweaking.


Hi DaGameFace, this had been a steep learning curve for me as well. Had the printer for 2 weeks tomorrow, so keen to get something out of it. The key to taking something like this on is patience.


On the list is to look at sorting the firmware. Had some information on the current settings with the documents that came on the SD card, however when compared to what was actually set on the printer via the LCD panel, the majority are different.
I have noted all the current settings so once I have reached a stage where I can print something, I’ll look at updating this.

I have some experience with Arduino, and have been collecting the important settings from this forum, youtube, etc.

Thanks all for you suggestions.

Not sure if you tried this but I had that exact same printer, from the same supplier on ebay as well also got it about 2 weeks ago so probably the same batch. I solved the clicking issue just by lowering the print speed down. The defaults were way too fast for the cheep extruder to handle. I now print at around 30mm/s instead of the default 80. I've also got the wrong thermistors and intend to replace them at some point, until then I'm just adding 15-20 degrees to the temperature setting.

Hi ianm1981

Aren't they fun. My tube was completely blocked at the top, solid metal still. I received the replacement via Amazon seller this morning, fitted, and am now extruding plastic. Whilst extruding, I also had the occasional clicking issue, so will lower the print speed, thanks for that.

I'll align the bed and go for the first print

How have you found the print quality?

It's required a lot of tweaking and I normally have to re align the print bed every few hours use. In general ive found the print quality to be pretty good. I've got some banding in the z axis but its not too serious now, I had to recenter one of the threaded rods as you found there was a bit of a bend to it. I did find a solution on here was to only support the rod from beneath and another forum member, awdorrin, made this part to replace the top bracket but Ive yet to try it out. I made a fan duct to take the air from the extruder heat sink and blow it onto the print which has helped some of the finer detail.

these are some of the earlier prints I did but its getting better each time.





If you want to have a go with the fan duct its on my thingiverse

Thanks for the fan duct link, I'll try that shortly.

Have managed to print a 20x20 hollow cube, not too bad, and the dimensions are correct. Had a slight bed adhesion issue, but happy for the first attempt, guess it is now a case of tuning in.

hi

I've bought a similar printer in januari, with a different supplier. I didn't have any problems at all. I will try the new fan duct and see if the results improve. This is my first printer, but the results are great.

Ianm,

Nice prints, I think they look smoother than what I've been getting.

Was that blue PLA or ABS?

Haven't had much time to play with my printer over the past two weeks due to work, but I think I'll have to try that duct you made.

I noticed with my printer that the Y belt was starting to drift to one side of the idle wheel at the front of the printer, causing some wear.
I printed a pulley guide that slides over the wheel (http://www.thingiverse.com/thing:1116216) which keeps the belt from rubbing the metal bracket.
Seems to have worked well so far.

-Al

That was all done with the roll of sample PLA that came with the printer, .25mm layer height and around 30mm/s speed. I've also noticed wear on the x and y belts already with a very fine layer of black rubber dust appearing on surfaces under the pulleys. So I think that's soon going to be on my list of things to replace. I'll have a go with that pulley bracket when I get home tonight.

I have the same issue with wearing of the belt, another small niggle to fix.

I have been working through some settings today to tweak the prints and have settled on been printing from Cura as there is erratic behavior (moving of the bed and random movements) when I use the SD card reader (also tried the files on the SD card provided), also on a couple of occasions the screen has become garbled.

I also have this printer and have experienced similar issues, "clunking" whilst feeding the filament and thermistors reading incorrectly (still not addressed this actually),
to help the clunking issue i printed this: [www.thingiverse.com] i printed it for the right side and rotated the hotend and motor assembly 180% degrees
re-drilling the 6 or 8mm hole (i forget) at the back of the L shape plate, it seems to have helped the clunking issue a bit.

I have since used this firmware (wrote over the original by accident,whoops!):

4) I3 pro&proB

I3 pro&proB(GT2560)
Marlin-PI3_Pro_B.zip
Marlin-PI3_pro_B
(299.21 Ki Downloaded 882 times

Found at: [www.geeetech.com]
Be sure to alter the configuration.h file to the same estep values before flashing, it also includes a few extra features which is always nice!

i am currently awaiting parts to completly rebuild the hotend (E3DV6) using: [infill3d.com] (thanks johngill1971 )
in the hope of completely eliminating the clunking issues for good.
to be fair to this inexpensive unit i have had some very good prints some well over 5+ hours without issue yes it takes alot of work and tinkering
but im fine with that.

Hi Mrp23

Thanks for the info on firmware and hotend, I have not been suffering with with the clunking at the moment.

I have some time today, so i'll see what progress I can make.

Brilliant thanks for the firmware link. That was the next thing I was going to start looking at. I'm planning on getting a dual head extruder and hopefully an auto levelling probe both of which require a few firmware tweaks which I was nervous to do without knowing I had the correct firmware on file.

Hi, ive just got that printer today. i think i have the mb setup right but would anyone beable to post a pic of theres with bits labled, as the instruction manual is use less. its that bad i cannot even find how to load the filiment,

im not new to 3d printers i have 2 CTC 3d's which work really well but wanted some thing diffrent and this is my first I3

Any advice would be great

Hi ettie1972,

If you are wanting to clarify the positions of all connectors on the gt2560 board take a look here
under interface layout: [www.geeetech.com]

what exactly is the issue with loading the filament?

Thought I’d give you all an update on the current progress.

Printing is getting better now that I am starting to understand the various temperatures and printing speeds that effect the quality. I started with Cura but have recently started to use Slic3r, which, for me anyway, seems to produce better results.

I have had no issues with bed adhesion at the moment, printing with PLA onto blue tape has proved reliable. In fact, the adhesion has sometimes been too good.

The current challenge is with filament feeding, I have had to slow the prints down dramatically with larger prints as the quality was becoming pretty poor. I have been looking at the ‘MK8 Extruder Aluminum Frame Block DIY Kit’ found on ebay. Maybe a replacement extruder is the solution.

Any advice would be appreciated, also, being new to this, can anyone explain what ‘Right Hand’, ‘Left Hand’, and ‘Normal’ means? Probably straightforward as searching for the answer has proved unsuccessful, so forgive me if this is obvious.

Hi,
I just got the same printer and I have issues.

- The temp readings are +20C - will solve that later.

- My motors are not turning properly. At first I couldn't get my motors to turn and only X felt like it's trying to do anything. I tried adjusting the pots but that didn't change anything. After a bit of reading I managed to get my X motor moving - although very jerky and inconsistent - by removing jumpers. I can move it in full, half and quater step setting. 1/8 and 1/16 doesn't work. I checked over the wiring many times and everything is as it should.
What can be a reason for that? Have I got a faulty board?
Also I'm yet to confirm it but 2 out of 4 of the drivers appear to be dead.
I am considering changing firmware to merlin posted above.

Hi artur k,

No expert myself, still learning, but I’ll try and give you some pointers.

The temperature issue is likely due to the wrong thermistors being fitted. They should have a resistance of 100kohms, the ones fitted to mine were 50kohms. Once replaced the readings were fine without any changes to firmware. I checked the Marlin config file for the resistors supported and fitted a 100k NTC 3950 sourced from ebay, and an NTC 100k from element14 (part number 135-104LAF-J01).

I had similar experiences with the motors. I was using pronterface to control the printer directly over usb whilst I got used to the functions and found it easier than using the LCD screen. It turned out I was forgetting to ‘home’ all the axis when first connecting, once this was done (one at a time to test the endstop switches), everything behaved itself.

I have found that the printer firmware to be setup adequately for my needs at the moment. I also initially beleived that I needed to update, and I probably will at some point, however I felt learning the basics before I jumped in too deep would be the correct path to take.

I hope these points help you make some progress, hang in there, I found it tough at the beginning also, it is worth persevering.

I have the same printer. Still waiting for the instructions manual (6 weeks). Still I engaged brain, did a bit of Googling, and managed to assemble. Actually there were very few real problems. The biggest was the X stepper mounting which disintegrated after a few days, the alignment of the motor was out anyway, so replaced with a steel slotted mounting. and the alignment of the Z limit switch, which was totally inoperative (needed a couple of small spacers. I've now done quite a few mods, and it runs pretty well. Changes include the following:
Bowden extruder,
adjustable Z endstop,
one motor mount,
clamps on the Z smooth rods,
knurled nuts on the bed levelling screws,
drag chain,
E3D hotend,
layer cooling fan.

Hi brs1701d,

I ordered this: [www.ebay.co.uk] in LEFT hand and received the one on to the left of the picture so i would say it would be which side the motor is mounted (maybe?).
Please note that part did not fit correctly for me due to the orientation of the block in the the L shaped bracket so i used the springs and screws with this and printed myself out of trouble!


As you can see in my picture i have the motor mounted to the right side.
one thing i noticed after assembly was that when i homed the machine the etruder was off the table by 10mm+ has anyone else found this to be the case?
with this setup now it is perfectly aligned to the corner of the bed .

Hi Mrp23

Thanks, great help, my motor is mounted the other way (I wonder if you can mount either way?).

Cheers

Mine was mounted to the left side before i modified the L shaped bracket to how it is now, it also keeps the motor rotating in the same direction, if anyone is interested i can pull it apart and take some photos?
For those on the standard assembly which hole (front or back) do you load the filament?

Quote
brs1701d
Hi artur k,

No expert myself, still learning, but I’ll try and give you some pointers.

The temperature issue is likely due to the wrong thermistors being fitted. They should have a resistance of 100kohms, the ones fitted to mine were 50kohms. Once replaced the readings were fine without any changes to firmware. I checked the Marlin config file for the resistors supported and fitted a 100k NTC 3950 sourced from ebay, and an NTC 100k from element14 (part number 135-104LAF-J01).

I had similar experiences with the motors. I was using pronterface to control the printer directly over usb whilst I got used to the functions and found it easier than using the LCD screen. It turned out I was forgetting to ‘home’ all the axis when first connecting, once this was done (one at a time to test the endstop switches), everything behaved itself.

I have found that the printer firmware to be setup adequately for my needs at the moment. I also initially beleived that I needed to update, and I probably will at some point, however I felt learning the basics before I jumped in too deep would be the correct path to take.

I hope these points help you make some progress, hang in there, I found it tough at the beginning also, it is worth persevering.

Thanks, I'll get those thermistors once I start the printer.
I tried homing, the problem is that the motors are not moving at all so cannot hit stops. One driver that is showing signs of life is acting weird as well. I only works in full step, 1/2 and 1/4 and only on low pot setting (full clockwise). In 1/16 it is still trying but unable to move. If I help it by hand then it moves but the distances are waaaaaay off.
I ordered a set of new motor drivers, to see if those were faulty. Contacted the seller as well, I'll see what he says.
In the meantime I tested heating elements and found that both are getting up to the temperature in less then a minute so all is well there.

I also have a question about the endstops. I received 3 endstops in NC configuration connected to XYZ MIN. The board has 6 ports for them. When I send M119 I receive back that XYZ MAX are tripped - is it the same on yours?

Quote
Mrp23
Hi brs1701d,

I ordered this: [www.ebay.co.uk] in LEFT hand and received the one on to the left of the picture so i would say it would be which side the motor is mounted (maybe?).
Please note that part did not fit correctly for me due to the orientation of the block in the the L shaped bracket so i used the springs and screws with this and printed myself out of trouble!


As you can see in my picture i have the motor mounted to the right side.
one thing i noticed after assembly was that when i homed the machine the etruder was off the table by 10mm+ has anyone else found this to be the case?
with this setup now it is perfectly aligned to the corner of the bed .

Having the hotend off of the plate makes for easy extrusion. Over the plate blocks this task.