Friday, 7 December 2012

Mendel90 updates

It has been a long road but I am now in a position to sell complete kits for Mendel90. My original plan was to use laser cut acrylic but the companies I got quotes from could not guarantee the holes sizes would be accurate enough to be tapped. I also found out that 3mm Dibond is stiffer than 6mm acrylic as well as being a lot lighter and cheaper. The downside is that the polyethylene core is too soft and the aluminium wall too thin to tap a thread into reliably. That meant replacing all the screws with nuts and bolts, which made the machine fiddly to put together. To fix that I reversed all the bolts and put nut traps in the plastic parts. The design still supports the MDF and acrylic variants with screws, but I only sell the plastic parts for these.

Picture courtesy of  Alzibiff, a Mendel90 owner who is also a photographer: thefullpicture.co.uk 
Because the underside of the base now has screw heads protruding, the machine has to have some form of feet to raise it. I added two aluminium square tubes, which also provide stiffness as they are directly under the stays. An added  bonus is that the wires for the Y axis can now run underneath the base to improve the appearance. Another advantage is that the printed cable clips can now be replaced by zip ties that go through holes in the panels.

I changed the default electronics from Sanguinololu to Melzi because it includes the SD card interface and fan drive on board and uses screw connectors rather than friction fit. These are the only connectors I have found to be reliable in the long term and it will allow me to offer a no solder version of the kit. After a couple of false starts I now have a reliable source of these and they are 100% functionally tested using the same motors as I provide in the kit.


I also changed the PSU to an ATX500 because I can buy them in the UK with CE approval and they come with integral mains inlet and switch, obviating the need for the kit builder to do their own mains wiring.  It is also shorter, allowing room for the Melzi (which is very long and thin). The downside is it needs a pair of load resistors on the 5V and 3.3V to get the 12V rail to be close to 12V under load. These are provided in the kit.


To stop the deeper power supply sticking out beyond the base I moved the right hand stay inwards. It is now directly behind the  Z bar that it braces, which is better from a structural point of view and gives maximum space for the electronics bay. A couple of plastic brackets hold the ATX PSU in place.


The build height is increased to 200mm as there is very little downside to doing so and it makes room for the Melzi electronics.

I added a spool holder which suspends the spool between the stays on 608 bearings using a couple of triangular brackets.



In order to turn the filament through 90 degrees I use a PTFE Bowden tube. That also has the benefit of removing any drag on the head when the extruder pulls filament from the reel. The only force on the head is that required to bend the loop of filament and the tube, which has only a thin wall.

The end of the tube is terminated by a printed connector with a flange that just sits on top of the extruder. That allows the extruder to reverse without having to push the filament back up the tube.

There is dust wiper on entry to the tube which consists of a block of foam squeezed into a smaller box with the filament running through a slot in the middle. It prevents dust that settles on the spool being dragged into the extruder.


I made a few tweaks to the extruder. I now use J-Head nozzles so I integrated a groove mount into the Wade's block. The nozzle is a tight fit and I press it in with printed jig and a vice with rubber jaws.


After the first five kits I found I could no longer get the J-Head MK4B and had to switch to the MK5B. That isn't long enough for a machine like Mendel90 because the bottom of the carriage ends up too close to the bed. I had to extend the bottom of the Wades' block so that it now protrudes below the carriage. In order to do that I had to make it a little slimmer to fit through the hole and that had the side effect of making the bearing housing symmetrical about the filament path. I think the reason it wasn't before is because there isn't room for the bolt heads on the motor plate side. I solved that by turning the bolts around and using captive nuts in the bearing block. That also makes the springs much easier to fit as the nut engages before the spring has to be compressed. The hob position is now further up the bolt at 25mm meaning more of the shoulder enters the bearing.

Other minor changes were that I lowered the motor a few mm so that it traps the head of the mounting screw  making it easier to fit to the carriage. I also replaced the spring that I used to retain the nut on the hobbed bolt with a lock nut and a star washer. They only need to be finger tight.

In order to be able to offer a solder-less version of the kit I made a tiny break out PCB for the extruder motor and heater connections.


I also made the socket on the end of the X cable an IDC version. That meant the pin to wire connections had to be 1:1, so I had to increase the number of pins from 9 to 15. The heater wires were previously doubled up to handle 2 Amp heaters but now I have enough pins for three wires giving about 4 Amps. There are also wires for a fan and a Z probe.

I simplified the X ribbon cable layout. Previously I had a pair of grounded wires acting as guard between the X limit switch and the noisy motor wires. Instead I simply moved the limit switch wires to the other side of the cable, where the quiet signals are. It actually makes the X end wiring neater and gives me the extra two wires for the extruder heater so that the cable remains 20 way, which is a standard size.


On the subject of ribbon cables: I increased the one for the bed from 24 way to 26 way making that a standard size also and two extra wires for the bed heater is not a bad thing.

In order to be able to print small items and items with steep overhangs in PLA I took a leaf out of Richard Gain's book and added a ducted fan to the carriage. I couldn't use his design directly because he has a longer nozzle mounted in a different orientation. This is my compressed version.


 The exit of the duct produces a ring of air directed inwards. The idea is to direct the air onto the part close to where the new plastic is being laid down without cooling the nozzle.


Because the Melzi only has a single fan output I removed the bed cooling fan but left the hole and fan guard for it. It is something I use to speed up production by cooling the bed rapidly at the end of a build, but the 80mm high airflow fans are expensive. They used to be cheap when they were used in PCs but they have all switched to quiet ones nowadays with less flow. If you want to add one you can hack a MOSFET onto the expansion port of the Melzi and control it with M42 in Marlin.

The OpenScad model now includes everything in the kit, which is everything needed to build the machine apart from some sticky tape used to secure the PTFE tubing. Most things are visible in the rendering but a few generate BOM entries only. These are things like wires and ribbon cables, which are hard to draw. Resistors, thermistors, sleeving and heat shrink are all drawn in places close to where they are used.

Having everything in the model is the only way to keep the BOM 100% accurate. I also re-structured the sub assemblies so that they reflect the order things are assembled rather than their placement in the machine. For example the Z lead nuts were in the X end assemblies because that is where they end up, but when assembling they are fitted to the leadscrews and then inserted into the X ends, so they need to be part of the Z axis assembly.

I created a detailed build manual for the kit in OpenOffice format. It links to a lot of pictures generated by the model so that they automatically update. The manual is also checked into GitHub, so there is a version matching each revision of the machine. I had started with instructions in the Reprap wiki but that soon become impractical as it can only represent a single version and all the images need to be manually updated. It can't link to images on GitHub for instance. Although the manual is for the kit version of the machine, it will also be useful to people making the other versions. The main differences are that different fasteners are used. The PDF version is here.

The first five kits were commissioned for a build a weekend hosted by the GIST lab in Sheffield during the university's Festival of the Mind. Due to various supply problems I only just managed to get all the parts together in time and then only with a lot of help from a couple of friends. I ran out of time completely to do the instructions so I stayed up all night and hacked some together. Despite that the build weekend went well.

Two of the teams completed their machines on day one and were extruding plastic. By the end of day two all the machines were completed, two teams were printing items downloaded from Thingiverse, another was extruding. Unfortunately two were held up by faulty Melzis. I hadn't tested them beforehand because I had five spares, but it turned out one of the originals had a small fault and none of the spares worked at all. Needless to say I won't be using those suppliers again!

The Derby Makers team won the "Golden Spanner Award" awarded for "the best demonstration of the Craft and Magic of Technology". Here they are printing.

Picture courtesy of Derby Maker Glyn Smith.
More pictures of the weekend here.

The build weekend was very helpful for ironing out snags. This lead to tweaks in the design and the instructions being greatly expanded.

Kit details:

Specification

Build volume 200mm x 200mm x 200mm.
Filament 3mm.
Nozzle size 0.4mm.
Footprint 465mm x 419mm.
Height 400mm, with spool 609mm.

Contents

The kit contains everything needed to get printing including ~ 50m of Faberdashery PLA. You will need a PC and some tools to put it together and run it, details at the start of the manual. Some things included in the kit are: -

  • Melzi electronics with Atmega1284P, ROSC shorted for correct microstepping, tested and programmed with Marlin firmware configured for Mendel90
  • Micro SD card for pause free printing, comes pre-loaded with all the software needed to print on Windows (Linux equivalents can be downloaded) and a USB to SD adaptor for direct connection to a PC.
  • 0.4mm J-Head MK5B hot end for 3mm filament, pre-assembled with thermistor, resistor, wires and sleeving.
  • ATX500 PSU with quiet fan and dummy load resistors.
  • USB cable.
  • Prusa MK2 heated bed with 2mm glass sheet.
  • 3mm aluminium composite panels CNC cut and drilled.
  • 5 NEMA17 43Ncm stepper motors.
  • 8mm hardened high carbon rods with h6 tolerance as required by the linear bearings.
  • T2.5 metal pulleys and polyurethane belts with steel reinforcement.
  • CNC hobbed bolt.
  • Extruder break out PCB.
  • 1% thermistors to avoid the need for temperature calibration.
The complete BOM is here.

The big advantage of the design is that the axes need no alignment to ensure they are orthogonal. The only calibration required is bed levelling, Z height and extruder flow rate. Details in the manual.

The price of the kit is £499, plus VAT in the EU, plus shipping. For availability check the forum post here.

109 comments:

  1. At last! It looks fantastic Chris. Best of luck with it.

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  2. £499? Blimey, you've done well! I spent more than that on a machine with fewer bits (e.g. no reel mount) and you have to make a profit too... Congratulations on reaching this point. I expect these to be pretty popular at this price point. What's your marketing plan? :-)

    Gerv

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  3. I had a look at the manual, excellent work!

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  4. Nice work, looking good

    Have you considered using Brass inserts in the Dibond I have used these successfully with Acrylic, you insert them into a drilled whole with a hot pointy soldering iron, much better than tapping.

    like these : http://uk.rs-online.com/web/p/inserts/0278590/

    regards
    Al

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    Replies
    1. I don't think they will work in 3mm thick dibond. I have used them in printed parts and they work great.

      Delete
  5. That looks damn good, I wish I had a need for yet another printer, because I feel like compared to printrbot with "sort of ok", this seems "quite a bit fussy about quality in a good way for not much money." I shall be recommending this to some friends.

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  6. Bought one of these last weekend, based on recommendations for the Mendel90 design on the RepRap forums, but only just saw this post today - hasn't realised it was the latest version! I must say the black Dibond is amazing, and the finished product looks much better than a £1800 Makerbot.

    Took me a total of 25 hrs to complete (2 hrs Thursday night, 6 hrs Friday, 5 hrs Saturday, and a marathon 12 hrs Sunday), though if you had someone to help, you could get it done a lot sooner, as the instruction are broken down well into separate tasks. Got to the point of everything built, connections tested, the Melzi wired up, late last night, but not actually plugged it in yet - hoping to be able to go through the test/setup procedures tonight and print my first little android. Just dreading that 'nothing happened' moment when I switch it on :)

    I must say both Chris (Nop Head) and Mary have provided great service (immediately posting first class a replacement fixing block I stupidly over tightened and cracked), and the attention to detail in the kit itself is amazing. I'd much rather this £500 kit plus a long weekend's build, that I have a feel and understanding of from physically putting together, than a shiny plug-and-play version for nearly four times the price.

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  7. I don't know if you are a fan of asciidoc, but its a really great way to generate a manual, and ideal if you are wanting to track the changes to the manual in github.

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  8. Hi Giles,
    I had never heard of it before, but it looks ideal.
    Thanks

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  9. Hi Chris,
    it occurs to me that if you can persuade that power supply to run a Raspberry Pi you could flash all the hostend software on to that. You could then offer a turn key 3D printer solution for another 30 pounds. Just add a monitor, keyboard and mouse.

    Good luck. I've just got my reprap Mendel up and running but I may well need a second printer!!

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    Replies
    1. Yes you could tap 5V from the dummy load resistor and easily power a Raspberry PI.

      Delete
  10. Thanks Chris for a great printer!
    In the long cold Siberia will soon get its mendel90

    http://pics.nashgorod.ru/photogal/1691/600_99dbc499ddd88f192d1b217297e24f8f.jpg

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  11. Chris, thanks for all the plastic parts. I can't wait until I have this Mendel90 put together.

    Side question, instead of a MOSFET hack for the bed cooling fan why not run the fan off a 5v line from the ATX power supply. Then add a manual switch to the line to turn it on/off. Or is that just a dumb way to handle this fan?

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    1. Yes you could use a manual switch because if you are not around when it finishes then you don't mind how long it takes to cool.

      Most fans are 12V though, especially if they are powerful ones.

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    2. okay, easy enough. My ATX has a few extra rails. So a 12v fan shouldn't be a big deal. thx.

      Delete
  12. By mistake I printed old parts but nevertheless I used them for building successfully.
    I use more simple method for bed bolting and easy leveling.
    http://roboforum.ru/download/file.php?id=26470&mode=view

    RAMPS and non modified PSU
    http://roboforum.ru/download/file.php?id=26464&mode=view

    I use DIY J-head. What is the nozzle height down from duct? 2-3mm or more?

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    1. Use a pair of nuts to let bolt rotating with slight friction. I use 2.4mm bit for drilling dibond and M3 thread cutting.Very tight.

      Delete
  13. Wow nice job. Looks really good.
    I'm thinking of building one for my own..
    Do you think the design would allow scaling to some extent?
    I was thinking about a printable envelope of 300x300x200..
    Apart from making my own heated bed and scaling, do you think I would need major modifications?
    Do you think I could keep M8 rods or would I need to use M10?

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    Replies
    1. Yes you could scale to that size. It will get slower as the bed will be a lot heavier and bed heater will also need a lot more power (both square laws).

      You could consider making the Y motor NEMA23, but that might require different electronics.

      I would recommend 10mm rods so they don't sag too much in the middle.

      You may as well also increase Z to 300mm because there is very little disadvantage to increasing the height.

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    2. There is a new Pololu driver DRV8825 that might help here, as it can deliver up to 1.8A without active cooling. This unit will fit on a RAMPS board socket.

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  14. I love the attention to detail -- very well done.

    Given that this seems likely to address all the sources of grief that I have with my Prusa, I'd like to cannibalize that into a Mendel90, but am wondering how much of it is actually worth keeping. Would you be interested in providing partial kits for people jumping ship?

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    Replies
    1. At the moment we are struggling to keep up with demand for full kits. Maybe in the new year we could look at doing one without motors, electronics and PSU.

      Delete
  15. Do you, or will you, offer kits of all of the non-plastic parts, for those of us who have printers, but want better ones?

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    1. Yes I have sold a kit without the plastic parts for £15 less. They are only a small part of the materials and labour in a full kit and not the limiting factor on the number of kits I can produce.

      Delete
  16. You say "The end of the tube is terminated by a printed connector with a flange that just sits on top of the extruder. That allows the extruder to reverse without having to push the filament back up the tube." I'm not sure I see how the extruder can avoid pushing the filament back through the tube.

    Some of the ABS I have here is on reels that are 5" in diameter; other reels are 6.5": will your design tolerate both reel sizes?

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    1. The tube isn't fastened to the extruder so when it reverses the tube and filament move together. When it goes forwards the tube is pulled against the extruder and then the filament has to move through the tube. The tube then takes the strain so the friction of pulling the filament off the spool does not drag the carriage.

      I don't think the spool holder will work with such small spools. For those you can suspend a pole across the two stays, like this http://www.thingiverse.com/thing:26793 or this http://www.thingiverse.com/thing:26463.

      Delete
  17. Do you have a rough estimate on what international shipping would cost for the kit? Specifically I am in Washington state in the U.S.A.

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    Replies
    1. Shipping to the US via UPS is £60 economy and £69 express. Economy is pretty fast, we shipped one on Friday and it is already in Louisville.

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  18. are you going to publishe all the parts on thingyverse aswell...
    with that i menth the real holder etc and the cheanged parts?

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    Replies
    1. No because it is too much work to keep it up to date as it has no version control. The advantage of Github is that if I update it while somebody is half way through building it the old version is still available with instructions that match it.

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  19. This comment has been removed by the author.

    ReplyDelete
    Replies
    1. Do you have kits ready to ship?
      What is the shipping costs to Finland?

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  20. I have a waiting list of orders to fill first, but should have a kit to ship by next week. Shipping to Finland is £40.50 GBP. PM me if you wish to proceed and reserve a kit.

    You will need a range of tools as outlined in the build instructions on Github but everything else you need for the build is included in the kit, apart from sticky tape grease and mains lead.

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    1. I should think about it... I first thought to build a printer by myself but then i found this and I don´t think I can get under that price if I invent it myself :) Do you have payment via paypal or what?

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    2. In the Content list it says that 20m of PLA is included... Which color is it? If I order more colors from faberdashery it is good to know.

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  21. Stunning job, what a lovely design - took a quick look at the well presented manual as well - excellent! Just a tip (last page), the hobbed bolt can be cleaned in situ using a 3mm tap, just roll the tap in your fingers against the grove whilst turning the gear. Do you sell the Dibond or would you be willing to disclose provider?

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  22. what program do you use for all the drawings?
    looks awesome
    graeme

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    Replies
    1. Hi Graeme,
      I use openscad for the design and that produced all the drawings.

      Delete
  23. Hi,

    can you tell me which firmware you prefer for the Melzi ?

    Oh - really nice job by the way :)

    Regards

    C

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    Replies
    1. I have only used Marlin as it seems to be the most popular. Repetier's firmware is probably worth a look as well.

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  24. Thanks. I'm happy with Marlin. It's what I'm currently using and I have no other experience :)

    Regards,

    C

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  25. Hi Nophead! First off, thank you so much for all your hard work!

    I'm about to build a Mendel90 (my first printer), but today I ran into a snag. I was able to run make_machine.py mendel (side note, It took me quite some time to figure out how to do it, and I can't seem to run that command again, when I try, it ignores that I typed mendel, and gives me the command parameters again, as shown here: http://puu.sh/1OcUa).

    Anyway, I ran main.scad, but after it was at 27% for a few minutes, it crashed with this message: http://puu.sh/1O9O0 (yes I checked I have the correct runtime libraries). Before it crashed, I was able to copy the openscad console (http://pastebin.com/imkn5aEn), however it seemed to be fine up until the last ~10 lines. It seemed to have finished everything, but then it broke somehow.

    I'm running Win7 Pro, OpenSCAD 13.01.08, Python 2.7.3, the latest version of Inkscape, and I downloaded your files today. I also had a friend with a similar setup try it, and his crashed at the same spot. Thank you again for your time. I am building a mendel90 as somewhat of a "senior project" (I'm 17 and homeschooled). Take care!

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    Replies
    1. I can't explain the first problem. It only gives the usage message if you don't give it any parameters, but I can see you gave it mendel, so it doesn't make sense. Also, if it worked once it should work again. It doesn't modify itself.

      The second problem looks like you pressed F6. That tries to make one solid from the whole machine and goes away for ages and crashes. You should press F5 to see the assembly views.

      Delete
  26. I have a proplem with the extruder fan, when I send M106 to the printer sometimes the fan starts and sometimes it don´t so I have to manually start it with my fingers, And when I turn on the extruder хеатер, the fan allways stop with a "ticky" sound... I think the problem is that it don´t get enough power. What can I do about it? New cables from the controller board?

    //Martin

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    Replies
    1. Seems like a wiring fault. The fan shares the 12V feed with the extruder but it uses 3 wires in the ribbon cable, which is plenty.

      Check continuity between the fan + and 12V on the Melzi. It should be a direct connection. Seems like maybe the heater wires are crossed so the fan + is connected via the heater to 12V. When the heater comes on it switches the fan off.

      Delete
    2. I just messured it with my multimeter and as far as I can see it is good conections betveen PSU+12in and fan red cable. But the heater is working well, it is only the fan that needs more power than it will get... I haven´t turned on the heater and the fan for that amount of time so I can see if the heater is heating up when the fan is on...
      it is 11,7V on the fan with extruder heater off, but when I turn extruder heater on it drops to 0,3v.
      Between fan connections on melzi it is 12V

      //Martin

      Delete
    3. You definitely have the heater connections the wrong way round at the Melzi end.

      Delete
    4. Do you mean I have to swap the heater cables on the melzi?

      Delete
    5. Yes, you must have them the wrong way round. The 12V of the fan can't be connected directly to +12V because it could never read 0.3V if it was. I think the heater lines are swapped so +12V of the fan is connected to +12V through the 5R6 heater resistor. When the heater is on it is connected to ground by the MOSFET.

      Check against the wiring diagram in the manual.

      Delete
    6. I checked the wiring diagram 3 times befor I turned on the power, but I missed that theese cables was swapped... now its working

      Thanks
      Martin

      Delete
  27. hi nophead, I was thinking about auto leveling Z axis... could it be done by checking resistance between nozzle and surface of bed? like with a VCC on the the bed surface and a probe on the hotend's nozzle, so you check readings, when you detect touching you go up by a % of layer height (some people use 100%, 50%, etc) and print, what do you think?

    ReplyDelete
    Replies
    1. It would be hard to get a reliable connection with the hot end because it becomes coated with burnt plastic and the brass oxidises quickly at the elevated temperature.

      I am developing a self retracting probe, a smaller version of this one: http://hydraraptor.blogspot.co.uk/2011/04/auto-z-probe.html

      Delete
    2. nothing will work? capacitance, resistance, or etc?

      Delete
    3. If the bed was metal you might be able to measure the capacitance to the nozzle but it would be very small. Most people use glass though.

      Delete
  28. Hi nop head ! Just finished my build, power up and testing with pronterface on Ubuntu 12.10 @ 250k. All checks out except when attempting test print, 'invalid attempt to message console' or something like that srolls up the screen, crashes pronterface and window closes. Relaunching pronterface, try SD print and same again [many times actually]. What am I doing wrong ?

    BTW kit was top notch although a challenge for SAE sized fingers !

    ReplyDelete
    Replies
    1. Hi Bill,
      Are you running pronterface from the console? It looks like perhaps it expects to be but you have launched it from the GUI.

      Delete
  29. I don't have a console [yet]. and it is launched from the GUI.

    ReplyDelete
    Replies
    1. By "console" I think it means the command line interface. I.e. "terminal" under Ubuntu. I.e. I think it is trying to print something to the terminal but since it was launched from the GUI, rather than the command line it doesn't have one.

      Delete
    2. Got it sorted ! Must READ directions ..... not skim ! Forgot to rename the file with .G suffix. did that and problem solved !

      Delete
    3. Sorted it out ! Forgot to rename file properly !

      Delete
    4. I suspect when the Marlin saw the .gcode file it wanted to invoke a process to convert the file .... All is good now , now to learn the rest of it

      Delete
  30. I'm guessing there is no shallow end to this pool .... I am now getting to ABS printing and want to print some spare parts. Am I correct in determining that the .stl s are generated by running the python script with all the executables required installed ? I wonder if there is some step by step instruction, listing prerequisites and things I need to know or where I might find it.

    Machine is working very well BTW, learning slic3r settings and what influences what. Selecting infill and solid layers makes sense but how does one discover what the part designer intended seems a puzzle..

    My brain hasn't been exercised like this for a while .... Thank you, I needed this !

    ReplyDelete
    Replies
    1. Hi Bill,
      The stl files are all available on github so you only need to build from source if you want to change them.

      The readme on github describes how to do it and the required packages.

      There is some info in the reprap wiki regarding the recommended infill for each part.

      I don't use slic3r or recommend it as it doesn't conserve geometry.

      Delete
  31. A happy Mendel90 user here. I wanted to upgrade extruder on mine, because at the moment, J-Head nozzle is mounted with two screws from side. I did not manage to file accurate grooves, and the nozzle is now moving when filament is retracted.
    Looking at the Wade's extruder in github: http://faili.wot.lv/tmp/2013-02-17_18-22-20.jpg I'm not sure what is the correct way to secure nozzle. Do you secure your nozzle with three bolts and washers, using the groove which is already present on J-Head nozzles?

    ReplyDelete
    Replies
    1. Yes three M3 x 15 cap head screws, M3 star washers, M4 flat washers and captive M3 nuts. See https://github.com/nophead/Mendel90/blob/master/dibond/manual/extruder_hot_end_assembly.png

      Delete
  32. I am having a problem getting gcode files to extrude. Recovered from a /boot partition and restored my software. Both slic3r and skienforge.... Couldn't run skienforge as distributed with your files as the pronterface options and the directory structure spell it differently.... ie or ei .Manually through pronterface it will extrude. Have gone through settings multiple times but no clues.... Skienforge reported after slicing 'It took 2 minutes 36 seconds to export the file.
    0 mm of filament used in this print'
    help !

    ReplyDelete
    Replies
    1. Hi Bill,
      Do you mean you could never run the files I sent, or only now you have restored some files?

      Do you just need what was on the SD card again?

      Delete
    2. Do you have copied the .skeinforge directory that was on the sdcard to your harddrive C:\user\name\ ? And dont change the setting in skeinforge to PLA, let it remain on ABS.

      Delete
  33. Awesome! Do you have kits without motors, electronics, and PSU yet? How much? I have lots of RAMPS1.4 and NEMA17s and PSUs allready.

    ReplyDelete
  34. £120 off the cost and the shipping might be a bit less.

    Note that the wires go through small holes in the frame so you will have to put the connectors for RAMPS on afterwards. The Z motors need to be about 47mm long.

    ReplyDelete
  35. Where do I change the Z travel distance?
    I just levelled the bed with dial gauge to almost perfect but now the nozzle is so near the bed at the first layer that only a little bit of pla is coming out. Or do I have to move the Z limit switch? Or is it changeable in Pronterface or skeinforge?

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    Replies
    1. You change the firmware as described in the manual.

      Delete
  36. I'm interested in getting a kit in the US. Unfortunately the forum at reprap.org is down at the moment. Do you have any kits available?

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  37. First great thanks to Nophead for this fantastic Kit and all the work behind it.
    After some initial test prints I decided to upload a new Z_HOME_POS, but Arduino wont upload the firmware with this message:

    "core.a(main.cpp.0):infunction 'main'
    c:\Document and setting\install\Windows\arduiono-1.0.1\hardware\Melzi\cores\arduiono/main.cpp:7: undefined reference to 'setup'
    c:\Document and setting\install\Windows\arduiono-1.0.1\hardware\Melzi\cores\arduiono/main.cpp:10: undefined reference to 'loop'"

    No idea what this means or how to solve it.
    No problem with initial calibration and upload, also printing seems to be OK.

    ReplyDelete
    Replies
    1. Hi Bo,
      I have no idea what a "arduiono" is. Please use the software and instructions provided on the SD card. That is known to work.

      Delete
  38. Sorry should bee arduino.
    I have followed your instructions and only used the software from the SD card. And as I wrote, everything worked ok when I first calibrated and uploaded the firmware.
    Now when I follow the update instructions in software section (24) and press the upload button (It says play button but I suppose it means upload button) the “compiling sketch” turns up for a few seconds then this message comes up in the Arduino window.

    “Error Compiling
    core.a(main.cpp.o): in function 'main'
    c:\Documents and settings\install\Windows\arduino-1.0.1\hardware\Melzi\cores\arduino/main.cpp:7: undefined reference to 'setup'
    c:\Documents and settings\install\Windows\arduino-1.0.1\hardware\Melzi\cores\arduino/main.cpp:10: undefined reference to 'loop' “

    ReplyDelete
    Replies
    1. I can't think why it would only work once. It works fine for me and everybody else that has has bought a kit and uses Windows.

      loop() and setup() are defined in Marlin.ino, which is the project file that you open, so it doesn't make sense that the compiler would think they were undefined.



      Delete
  39. It is working, without doing anything, so some stupid mistake from me. Maybe I was in the wrong Arduino window when trying to upload.
    Sorry to have bothered you but the software section is not easy for a total newbie, being a mechanical engineer.
    But again, working in machine design for many ears, I appreciate the amount of work put into this project. And with the impressive result I can only congratulate you.

    ReplyDelete
  40. Bernard PENDERS belgique le 9 avril 2013
    Hello Chris,
    Thank you for the beautiful Mendel90 what your toy, I'm delighted.
    I want to use-host Repetier to manage the printer. I would like to know the settings for printer setup in Mendel90 repetier-host.
    I use Skeinforge to slice 3 mm PLA 220 ° C and 70 ° C for the heating bed.
    Thank you for your response
    Bernard

    ReplyDelete
    Replies
    1. Hi Bernard,
      Please ask in the Mendel90 forum. I have never had enough time to try Repetier host, but other people use it with Mendel90.

      Delete
    2. I only use the host to select which file on the SD card to print and manually control the extruder when changing filament. Although Repetier host looks nice it won't actually make any difference for me, which is why I haven't spent any time getting it to work.

      Delete
  41. This looks great. I'm looking to build my first RAP and am thinking that your design is what I want. I'm wondering - is the current kit a "non-solder" version?

    Or is the non-solder version something that is forthcoming?

    I'm not in a major rush, so if the non-solder version is upcoming (maybe with other changes?) then I'd wait. Otherwise I'll need to refresh my solder skills. Thanks!

    ReplyDelete
    Replies
    1. No the current kit requires a little soldering. Have a look at the manual on github to see what is involved.

      To make a non solder version would require me to do the soldering and I don't have time while people continue to order the current kit.

      Delete
  42. Hello, do you still sell the Mendel90 kits? I need one :)

    ReplyDelete
    Replies
    1. Yes, certainly do. Get my email address by following the link to reprap forum and then clicking on nophead.

      Delete
  43. Hello, I want to buy a Mendel90 printer from you, is the kit still available? Can it be customised with different electronics, extruders and hotends, or is it a exact kit? Hope to have the chance to collabotate, good luck!

    ReplyDelete
    Replies
    1. Yes we have kits available. We only sell one version but we can leave out the electronics and reduce the price by the cost of them to us.

      Delete
  44. Hi,
    I'm interested to buy one.
    I remember I saw a page for ordering but I can't find it back !
    where must I go ?
    best regards.

    ReplyDelete
    Replies
    1. The link is the last line of this article.

      Delete
    2. I'm sorry I haven't succeed.
      if I click on the "here" link I get to a page of reprap.org
      called "Mendel90 complete kits for sale: updated".
      I need more help !

      Delete
    3. Just click on my name on the forum post to get my email address and send an email with the information requested at the bottom of the post.

      Delete
  45. I assembled the mendel90 kit a while ago... Since I have a spare fan for the bed, I am now trying to make it run on melzi, I followed instructions on the sanguinolu fan hack, installed the required mosfet, but it doesn't seem to work with Melzi. Could you update your original post for melzi hack? Is ther modifications to do in the firmware?

    ReplyDelete
    Replies
    1. It works just the same except you need to use a different I/O line as the one I used on Sanguinololu is already used for the fan on Melzi. The pin out of the connector is different. It doesn't have a 12V pin but you can get that from the unused fan terminal.

      You don't need to change the firmware but the port number will change.

      Delete
  46. You were talking a while ago about putting the Y motor in the back of the machine, so the wiring is shorter and it is easier to adjust the idler. Why did you decide not to do this?

    ReplyDelete
    Replies
    1. It would mean the bed cable would have to come to the front and then be a bit longer longer so I decided against it.

      Also any changes are a lot of work when selling kits as the manual has to change, the gcode for the CNC, wire lengths, etc. All the work in progress has to be synchronised. The only way I can find time to make changes is to stop making kits and then a backlog builds up so I only change things if I absolutely have to.

      Delete
  47. Hi Nop Head,

    I was just curious about your ribbon cable system. Are you powering the heat bed through it? If so, how did you get around current issues? I've been thinking about trying it on my Prusa i3 as a tidier way of getting power, and the temperature sensor connection in one simple connector.

    Any advice?

    Many thanks,

    Rick

    ReplyDelete
    Replies
    1. I use 26 way cable, two for the thermistor and 12 for each of the power connections. That works out at about 1mm^2 of copper, which is enough for about 16A.

      Delete
  48. Hi Nop Head,
    I wanted to asked what do you mean in the PDF manual when you explain the wiring of the PSU...
    "Cut one of the black wires to a length of 240mm and one of the red wires to 280mm, strip
    them, add 15mm of 3.2mm heatshrink and solder to the 10R (gold in the kit) dummy load
    resistor.
    2. Cut another black wire and the green wire to 230mm, strip them, twist together, sleeve with
    15mm of 3.2mm sleeving and solder to one end of the 4R7 resistor."

    What I dont understand is the value of the resistors, in our country for example for a 4700 Ohm resitor we say 4K7 , a 4.700.000 we say 4M7, so I dont understand what the "R" means.

    Thanks very much
    Best regards.

    ReplyDelete
    Replies
    1. 4R7 is a standard notation for 4.7 Ohm. I.e. R means no multiplier, just Ohms.

      Delete
  49. Hi,
    You wrote in this post.."I made a tiny break out PCB for the extruder motor and heater connections."
    can you publish the file / image / pdf for making by my own this little PCB ? I searched in GitHub, but did not find it.
    Have nearly all parts printed, only big parts are awaiting that power outages finish here in Argentina.
    I'm thinking to use an UPS (I already have a gasoline power plant) , I am tired to trow away half big parts unfinished.
    Thanks very much.
    Regards.

    ReplyDelete
    Replies
    1. The Kicad designs files and the gerbers are on my github as a stand alone project.

      Delete
  50. Ordered the Mendel90 and received it within 2 days.
    Built it over the series of around 3 evening, I have to say your instructions are first class!

    I was a touch nervous about flicking the power switch, but all was perfect.
    Printed first time.

    The bed leveling and tweaking the nozzle height took a little practice, but I would say it worked a treat.

    My only challenge now is how to set up my products for printing.
    Creating STLs is fairly straightforward, but arranging them (orientation) and placing on the Bed is still a dark art.

    Any suggestions for the best Software tool for doing this.
    Repetier looks good as I can set out the Bed and rotate from within the program, what would you suggest is the best program?



    ReplyDelete
    Replies
    1. Netfabb Studio can easily rotate objects and place a nominated side on the bed.

      I now only use OpenScad for designing parts, so I always design them in print orientation and then rotate and translate them when used in assemblies. I also lay out multiple parts to print in OpenScad.

      Delete
  51. I've started looking for info on auto bed leveling that others have put on other printers. I have yet to find anything mendel90 or melzi related. I recall there is a pair of pins on the extruder breakout board for that future development. Have you done anything further on it ?

    ReplyDelete