Late last night I plugged everything in and pressed that power button in back… and the Sumpod came on, and better yet, no smoke!  Just have to load the firmware…but that is ready to go.

One complication in the wiring (which will be in the forthcoming documentation ) is that the LAN cable meant to wire the LCD just didn’t work.  The problem is that most LAN cables are meant for insulation displacement connectors, and not soldered.  Mine would not take up any solder, almost like trying to solder aluminum.  The stranded wire is silver in color but believe me, it will not solder!  So, being economical, I just made up a replacement wiring harness from left over stepper motor wires.  I knew those would come in handy!

My Sumpod is completely wired as of this afternoon!   I took lots of pictures along the way, but I still have to finish the written documentation for all of you.  And, there is one more really important test:  power it up and see what happens!  Actually, I do not want to release a set of wiring instructions unless I know for sure that they are right.  Still flying blind (although the RAMPS 1.3 page on reprap.org would be all you need, other than the LCD) I did add a few touches of my own.

For one, I expect to change hot ends so I used a 4 pin locking Molex connector for the thermistor and heater.  That way all you have to do is unplug the Bowden tube and disconnect the Molex connector and you could substitute say a dual extruder or some other hot end (like that from makergear.com).   Also, I used Teflon insulated wire for the connections to the heater.  You can certainly use the excess stepper motor wires, but from past experience I expect the vinyl insulation to get degraded over time.  I also decided that the fan would run with the heater, or otherwise you would have to run one additional wire to it (constant power).  So, we will see how that works.  At least that way the blue fan lights are on when the heater is running.

Another change I made was to use hot melt glue to fix the wires into the channels in the walls.  My nylon wire clamps didn’t fit into the slots neatly (the slots were too narrow).  Sure, I could have cut out the MDF so that they would fit nicely flush in the slot, but the speed of the glue approach was nice. So, I just used my miniature craft gun to get into those tight spaces.

So when will the wiring instructions be done and ready for you to download?  I will try to get those out over the weekend, so long as the “blue smoke genie” doesn’t get summoned from the Sumpod!  Thanks for your patience! – Eric

No I haven’t gone off for a “long winter’s nap” but rather my day job has been keeping me very busy.  The wiring is going well and as before, I have lots of helpful suggestions.  I am expecting to get this posted here by Friday, November 18.  What I am aiming for is a thorough and clear wiring procedure so you will be able to get it right the first time.   Thanks for your patience! Hopefully your build of the mechanical side is going well in the mean time. – Eric

The stepper driver boards are a remarkable product of modern electronics technology.  However, I’ve seen some comments on other boards that folks may have released the “blue smoke genie” out of the bottle (or fried the driver chip, to say it more directly).

The particular chip in the Sumpod kit that does the stepper motor magic is an Allegro A4983.  You can see all the technical details here:

http://www.allegromicro.com/en/Products/Part_Numbers/4983/

While a robust chip for the size, it is subject to one particular issue – there is no overcurrent protection.  That small potentiometer on the driver board is a critical adjustment — too high a setting and you will likely fry that driver chip.  With too low a setting your stepper motor will either not go at all or miss steps and stall.  Shorted stepper wires will smoke it quickly!  This could even come from poor soldering of the header strips to the board. Also, removing a stepper motor connector while the power is on is another way to get that smoke genie appearing.  I’ll be explaining this all in detail and covering how to set the potentiometer in upcoming build instructions.

There is also an updated chip from the same company that makes the A4983 — it is their A4988.  This is a drop in replacement and does have overcurrent protection built in.

http://www.allegromicro.com/en/Products/Part_Numbers/4988/

Pololu Electronics has it here in the same form as you received in your Sumpod kit: http://www.pololu.com/catalog/product/1182

Perhaps Richard has already changed this in kits shipped later than mine, so you might check if you have the A4988 instead.

Thus the best way to put the smoke genie back into the bottle is to replace any burned out driver boards with the newer A4988 model.  This is not entirely foolproof — you can still get smoke from the A4988, but there is a better margin for success!

Just a quick note about these important parts.   In my build instructions, I mentioned cleaning the rods to remove adhesive residue.  While this is very important, it also removes any oils from the surface (though as received mine were pretty dry).  A light coating of oil on the rods is important to smooth running and low friction.  If you look at the end of the bearing, there is a rubber seal.  If the rod is dry, this seal can stick to the rod and make a lot of friction.  I used a thin machine oil typically used to lubricate gun parts (please no comments about Americans and guns! 🙂 ).  A similar oil is that used to lubricate sewing machines, or a brand we have here called “3 in 1.”  Put some on a paper towel and run it over each rod.  That should make things nice and smooth!

In professional FDM machines a special high temperature silicone grease is used.  This is in part due to their use of a heated build chamber. I’ll be talking about lubrication of the machine in a later installment and some options for keeping the friction to a minimum.

OK, now on to the hot end construction.  Not all that bad, really, but a bit frustrating as you will see.  Based on some e-mail exchanges with Richard, your hot end parts and construction might be different.  Thus, as I was part of the first campaign, I’m sure he has incorporated many comments from early builders.  You get that benefit if you waited for the second or third batch!  If you are in that group, do share some pictures of the changes!  You can download Part 3 here: SumpodBuild3

The next installment will cover the final (hopefully) steps to complete the unit. This is primarily running wires, hooking everything up to the RAMPS board, some chassis wiring (power runs) and hot end connections.  I’ll probably devote a fifth installment to loading the RAMPS firmware and setting it up to work with this machine.  My intent is to use ReplicatorG here so a machine profile will need to be created.

And I guess if time permits, I’ll also collect some post-construction thoughts on improvements and experimental changes.  Of course, I want to get that first print out of the machine to prove it works!

This second installment of the build instructions completes the mechanical assembly of the Sumpod.  The right side panel is left off for now not only to do the assembly, but also to allow for final wiring.  Sypher, thanks for your comments on the pictures and I’ve tried to keep the backgrounds clean and include lots of closeups.

The next installment will be building the hot end.  Lots of interesting stuff there!

Sumpod Build Part 2

I decided to put the build instructions out in pieces and as .PDF files.  That way it doesn’t clutter up the blog posts and also provides for an offline copy.  The file is here: Building the SUMPOD_Part1 so enjoy!  And, do feel free to provide constructive criticism to improve the documentation.

Lots of parts!

Additive manufacturing is not only a hobby of mine, but also part of my day job as a college professor.  Recently, through a crowdfunding site called indiegogo.com, Richard Sum offered a new fused deposition modeler kit called the “SUMPOD.”  I ordered the kit in late July and it arrived in late October, just last week.  Patience is a virtue but I will admit I was getting a bit frustrated with a number of shipping dates being missed.  But the wait is over and I think you will see it was well worth it.