The RepRap Saga Part 9: Fix It!
by George on Aug.29, 2011, under Projects, RepRap Mendel
This is the ninth post in a blog series detailing my efforts to construct a RepRap Mendel, an open-source 3D printer. For the rest of the blog series, see here.
Introduction:
Previously, the Mendel blocks were constructed and everything was put together. Then came the lengthy process of machine calibration. I was closing in on a successful first test print, and victory looked assured.
During machine calibration, I tried to fix an axis issue using the “latest” firmware from Mendel-parts, only to be mortified as the latest firmware proved to be completely non-functional. Desperate to make things work, I switched to the Sprinter alternative firmware and Printrun software toolsuite. The extruder heated up and turned, the stepper motors moved, we were ready to try a test print!
I took some 3mm ABS plastic and fed it into the extruder. In pronterface, there are a number of pre-defined temperature settings, one of which is 230 celsius for ABS plastic. I dialed that on and watched the temperature rise…
Craaaaaaaaaaaap:
And looked on in horror as the temperature sky-rocketed well past 230 celsius all the way to 265 degrees celsius. That’s right, the PID control system was so poor that a 35-degree temperature overshoot was deemed acceptable. The funny thing is, at 265 celsius ABS plastic starts to burn. The plastic in the nozzle carbonized into a hardened, unmeltable substance, completely jamming the hotend.
Mendel is designed in such a way that successfully doing work on the hotend requires ripping apart the X-carriage block, a considerable work effort. Not wanting to do that, I attempted to save the hotend by forcefully clearing it. I started hand feeding plastic into the hotend, and watched as a paltry amount of blackened plastic came out the end. Things looked like they were working, until plastic forced its way through the hotend’s kapton insulation. Craaaaaaaaaaaap.
I shut down the machine, and, when cool, pulled the X-carriage block off the X-axis and disassembled, granting me access to the extruder. As I had hypothesized, the hotend was “shot”. Hardened, unmeltable plastic everywhere, and it had forced its way through the screw threadings in the hotend, locking the parts together very thoroughly. Attempting to unscrew the nozzle with a pair of pliers, I broke the nozzle in half. It was official, I was going to need to buy a new nozzle. Craaaaaaaaaaaap.
Replacement Hotend:
I went back to Mendel-parts (not by choice, but only because they had the only hotend I could absolutely guarantee would work in my machine), and ordered a replacement hotend. Mendel-parts, who continues to charm me with their lack of customer service, wooed me further by requiring a 25 euro minimum order and charging flat 25 euro shipping. Still, they will send you your stuff if you give them your money, so I had a replacement hotend roughly a week later. An extruder test, thermal overshoot test, and some reassembly later, and I was back in business!
The Reprap build is ongoing, but in the meantime, be sure to check out our flickr set for the latest build photos!
September 8th, 2011 on 6:57 PM
First of all let me say – Well done mate!! I think I understand your frustrations fully. I have been involved in other projects requiring long learning curves and lots of information exchange. What I soon discovered is 1) that the “cognoscenti” expect new users to go through a trial by fire period just to prove they are serious about the endeavour. 2) That there are unscrupulous entrepreneurs out there who really don’t give a rat’s ass about creating a loyal customer base (funny really). 3) That attracting new users by making it easy to get into this great new way of making things is not a consideration in business. 4) They do not care for the principle that if you run a business you can make more money out of new users than you can from old users then the new users become your consumables buyers providing ongoing turnover. 5) That you generate business by getting your new users to recommend your product to friends. And lastly, how do you do all this? By providing reliable, well written, step-by-step instructions that get your new users using your product confidently and follow that up with consistent support.
None of the above is in evidence here, infact it could be said that Camiel is consistent…consistently bad. I can say that because I ordered one of these kits – from Australia and this guy’s support is about as useful as a glass eye.
With the site, there is STILL no detailed build instructions (build/test – electronics/extruder) for these things on the site. Frankly how they manage to call this a KIT with so little support documentation available is laughable. Then you get the idiot “anointed” saying to customers that they should talk on forums/do research/ask questions…these are the guys I referred to earlier. They are the maladjusted wallys who are looking to establish their own intimate social scene. What a laugh.
The fact remains that Mendel-Parts has a looong way to go before it is anywhere near a KIT supplier.
I have been into UAVs for some time and I have been helping personal UAV enthusiasts to get into the hobby. I started building a Mendel when I realised that the CNC router I had built was great at cutting but I needed to extrude parts as well in order to achieve the full end-to-end design chain.
In my assessment, these guys are Keystone Cop level.
BTW – forget Gen6, go RAMPS instead.
Good Luck
Juan
September 8th, 2011 on 9:06 PM
Hey Juan,
Thanks for your comment
“infact it could be said that Camiel is consistent…consistently bad.”
I’m told he is a good developer and person by those who know him far better than I. That said, he doesn’t seem to be much of a people person, and the same goes for the rest of his staff. I suspect they’re making decent money from their business, so it would REALLY be in their best interest to hire a good customer support person who’s willing to help the customer. I can’t recommend Mendel-Parts to any of my friends. I’ve faced many hurdles in my build thus far, and a very large portion of them dealt DIRECTLY with the Mendel-Parts products.
“BTW – forget Gen6, go RAMPS instead” So I’ve (retroactively) heard
I think I have Gen6 working well enough to do a few test prints, which I’d prefer to do prior to shelling out for a completely new set of electronics…
September 8th, 2011 on 9:11 PM
Oh, also, I checked out your site. It looks awesome! Keep up the good work
September 11th, 2011 on 6:07 PM
Hi George,
I think you are right about a)Camiel not being much of people person b)M-P making good money from the business c)They desperately need to inprove their support capabilities.
I can say that quality control lacks (at least as far as my parts were concerned). Many of them were printed with too big a “step” resulting in “fluffy” consistency which weakened the part forcing me to re-make many of them. This I was lucky enough to able to do on my CNC router. Frankly, I suspect this happened because they were busy filling orders and larger step settings means faster output, less material used hence better profits.
Anyways I’m over this dude. Thanks for the encouragement with my site. I will be adding sections for the CNC project and the Mendel project as time permits. You are welcome to get in touch with me any time. If you ever want to build anything I am connected with just fire off your questions and I will help.
Cheers