PeterE builds a 3d Printer

[Pete W.]

Hi there,

Please forgive me if you know this but a wire finger guard has much less flow resistance than a panel of sheet metal with lots of holes, even if the unobstructed areas are the same. 

[PeterE]

Hi Pete W,

No need to forgive, even if I did know. 

The effect comes from the wire profile itself.

I am going to use chipenters idea and move the finger guard to the outside of the fram and at the same time secure the PSU to the frame wuth the guard screws. Will look neat and tidy.

BR

/Peter

[PeterE]

Some work done to make a largish hole in one of the side triangles. I decided that the best side would be right under where I put the graphic display which means the left side seen from the front of the machine. A 120mm hole becomes quite big  but we do want as good path for the air stream as possible.

I added a strip of the same ply using both screws and glue to avoid geopardizing the structural stability of the diagonal side. Now I am at it to clean up the mess after making the hole.

It also turned out that the screws that hold the finger guard also holds the fan itself in place so i decided to use only the two lower screws to secure the PSU to the fram. That should be good enough.

Then one more little bit must be done before starting to clutter the machine up with cabling. A small bracket for the PTFE filament guide tube on top of the extruder. The base design is not made for such a thing, but I found a way to include it.

Then there will be some days with sanding and painting to hide the worst mess-ups from hole making.

/Peter

[PeterE]

Since it is weekend I got some more done to the printer.

The filler had dried nicely so on with the first coat of paint to hide the worst blemishes :-)

The PSU is placed a bit from the board as the paint is wet.

Now on to the smallish bracket for the holder for the PTFE-tube that willguide the filament to the feeder on the extruder. It looks like below when placed on its "back".

Two tabs with M4 holes wil hold the bracket in place by using the long screws/threaded rod that will hold the pressure springs for the feeder.

The tabs are pushed down into the nut pockets and then the bracket is placed flat and securely in place.

Finally, the mount for the PTFE tube is screwed in place into the larger (1/8" NPT) hole and the filament is nicely guided straight into the feeder.


Weekend job done!

/Peter

[PeterE]

Getting closer to the end of the mechanical and woodwork. The PSU is in its final place and secured with two stainless sheet metal screws 4.8x20mm through the side triangle and into the finger protection on the fan.

Before fitting the PSU I added the cables I will need and for now leave the cable tail until the rest of the electronics is in place.

The central unit - the Arduino - will get its place between the top of the PSU and the top of the portal.

The picture shows more cables on their way. The set from the extruder and the ones from the stepper motors. I cannot do very much more before the Arduino is properly loaded and all applicable drivers installed which is the next step in the build. Well, apart from assembling the heated bed of course.

/Peter

[chipenter]

Its looking good ,I have just got my Arduino sorted , some hard learned tips don't change anything compile it first , that way any error messages are something you have done , and leave the com port as 0 in config h , I am using Marlon and Repetier as it has a setting for cnc router  in printer settings .

[PeterE]

chipenter,

Thanks for the tips, very useful! 

/Peter

[picclock]

Hi PeterE

Back from hols now. Re marlin configuration and configuration_adv header files. Editing these is easy, but its also very easy to make errors  . IMHO the best way to edit them is to use an external editor, like programmers notepad or Ultraedit. These programs display the comments in the file in a different colour to the active parts of the file, making it easy to see which options are enabled. Before editing make a copy of the files and leave in the marlin directory. That way if things go south its easy to retrieve an earlier version. You can do this in windows by right clicking the header file, then selecting copy, then right clicking again and selecting paste. Windows will then helpfully put ' - copy' after the file name. I generally amend this to something more useful. It can be very informative to insert comments near the top of the file to indicate the state of play. As long as the line begins with a double backslash it will be ignored by the compiler. For multiline comment sections use /* to begin and */ to end.

Forgive me if this sounds a bit patronizing, but I had many years teaching this stuff at a technology college, so feel free to ignore.

For the Arduino environment its best to keep the path lengths as short as possible. I installed Marlin to C:\Firmware\Marlin.

Hope this makes things a bit easier

Best Regards

picclock

[PeterE]

Hi picclock,

Have been on a work trip for a few days so read this when back. Thanks for the tips, I will set the electronics up together with my son who is computer science educated at university level  I need his help to make sure I do things right, and I think  he will find it fun just because, if you know what I mean.

We will hvae a good time to make this fly.

/Peter

[PeterE]

Got some extra time in the shop today as I was off work after the business trip. This meant I could start with the electronics and load the Arduino with its programs. I enrolled my university-educated computer knowledgeable son as extra support for the program handling. He is more well versed than I  am and thus good to have close for questions etc.

The Arduino, the central unit, will be placed above the PSU as shown before. Now it begins to get more complete with the rest of the boards and some cabling.

Here we can see the RAMPS board on top of the Arduino board, and the display adapter on top of the RAMPS board together with the five stepper drivers. Then all the different smaller and larger boards are assembled.

The driver boards must be fitted so the little trim potentiometer is "pointing" towards the display adapter to be correct. If not they will burn and probably take the rest of the electronics with them.

To be able to set everything up it is also necessary to assemble and mount the heatbed. According to recommendations on the reprap pages I will use a piece of cork sheet as heat insulation below the heatbed. (This is a piece from an IKEA set of cork place mats cut to fit the heatbed size.)

To make room for connections I made a cut-out on one of the edges, and then cut off the corners for the leveling screws.


Connect power supply cables and indicating LEDs on the heatbed. I use 12V DC for mine, so I will connect +12V DC to terminal 1 and -12V DC to terminals 2 and 3. A 1 kOhm resistor is soldered onto the board as is two LEDs. The LEDs are fitted in opposite directions to be able to signal whatever polarization is used. All according to instructions on reprap.

The LEDs and the resistor is fitted to the underside of the heatbed to enable the glass plate to be flush with the upper side of the heatbed. The LEDs must have sufficiently long legs to be possible to bend to be seen outside the heatbed edge.

The last component on the heatbed is the thermistor. I used a small blob of heatconducting paste to get a good thermal connection. I only needed the smallest amount and this still can be used for a lot of things.

To avoid loose cables and to secure the thermistor I used a piece of metal tape.

Then all electrical parts are in place on the heatbed. Here it is turned over on its proper side on top of the cork sheet.

I am thinking of how to fix the cork sheet to the heatbed, Glue is one way and some strips of the metal tape another. I will probably start out with some metal tape strips as this will make it easier to do service later on.

So far so good. Tomorrow it is time to make some anchors for the heatbed leveling screws with their springs. Then to fit the heatbed and cables to the build plate base ply.

Today's part done!

/Peter

[awemawson]

Does the psu run warm? If so the Arduino should be below not above.

(This is the industrial computer support part of me speaking from 30 years fixing things where the designer didn't think!)

[PeterE]

Hi Andrew,

Thank you for the info, very useful!

To be true I actually don't know yet ... haven't got the thing completely up and running.

Have tried to avoid heat from the PSU affect the electronics by having the air stream from the PSU fan to draw from the rear of the PSU and out through the side of the frame (can be seen above). That should avoid a direct air flow heat at least,

Then I have heard that the stepper drivers may become quite hot and thus require additional cooling by their own fan. This is something I will have to find out as the whole contraption starts working ;-)

/Peter

[picclock]

Hi peterE

Looks like your going great guns. I've just finished glueing the cork sheet to the back of the bed heater. Good to hear your son is helping - father son thing can be good. I measured temp rise of 104C with small heatsink on z driver. Made larger heatsink. Will update blog with piccys when I get a chance. Good to see your progress.

Best Regards

picclock

[PeterE]

Thanks picclock!

Oh, what kind of glue do you use to stick the cork to the heaater? and what kind of glue/tape do you use to stick the heatsinks on the stepper drivers?

BR

/Peter

[picclock]

Hi PeterE

I had some 'duff' lowish performance silicon heatsink plaster lying around which I used to glue the cork. Halnziye Hy910 is the code. Seems to be OK. rated for extended temperatures. Its soft enough for removal even when fully cured. Would have used JB Weld for permanent fixing at elevated temperature but you would have to destroy the parts to remove it. For temperature tests on drivers I used Akasa thermal adhesive tape.  After measuring and test I replaced the tape with AG TermoPasty for a permanent fix. Measurement was made with a thermocouple on the underside of the driver chip pcb, so pretty accurate. For tape I am using Kapton tape for its high temp properties.

However, there are some areas of concern. The thermistor measures the temp of the pcb, not the temp of the glass surface. Whilst it is easy to set the pcb temp, the temp at the top of the glass will show great variation. Drafts from movement will help conduct the heat away, the thermal resistance between glass and pcb is likely a variable high number. So not exactly precision. However, it may be adequate for this application. Short of packing the space in between with thermal grease and hoping little improvement seems possible. Will do further measurements when setup and may modify it to take a therocouple sensor attached (probably clipped) to the printing surface of the glass.

Re Z axis movement. How have you solved the angular movement/change of height issue with those couplers. I have two but am not sure about using them. My current thinking is plastic/rubber sleeving, alowing the threaded rod and motor spindle to touch, with the rod end rounded, so point contact. The sleeve will allow small angular errors with consistent radial position. Clamps at motor and rod ends will ensure no slippage. Have you any thoughts on this matter 

Best Regards

picclock

[PeterE]

Hi picclock,

Thanks for the info re glues. I used a contact adhesive to try to glue the cork to the heatbed. I know it is on the borderline temperature-wise, but it is a try-out. As yo8u perhaps saw on the previous images, I have used thermal paste for PD processors to connect the heatbed thermistor to the bed and the glass plate will be flat on (at least from start .....)

The heatbed is now attached to the plywood baseboard on the Y axis.
I started with a piece of the left-over stainless 8mm bar.

From that bar I made three top hat-like bushings that I glued into the ply at the proper places for the screws with the springs.

To avoid having to make a 3mm thread all the way through the 13 mm bushing I drilled it out about half way from the bottom. Threading went very nice and then the bushings were glued in place in the ply board.

With the heatbed in place I started with how to lay the cabling so it does not get itself entangled in the machine. A combination of small plastic cable guides (the white ones on the base board), and spiral tubing, I think I got a setup that may work.

The white cable guides are good for just laying the cables inside to stay out of the way. They are also well protected from mechanical happenings.

The cables from the X-axis motor and its end switch got their own piece of plastic spiral tubing. The cables are held together in the end close to the motor and the spiral then enters a 10mm hole in the portal to guide them towards the electronics on the back side. Did this as it turned out that the length of the cables were is some cases just a tad short compared to what could have been for ease.

I also did the same with cables for the extruder carrier with all of its cables The heatend, temp sensor, fan, and extruder motor. They got an own 10mm hole right beside the first one.

This way I can secure the cables on the rear side nice and tidy and no cables will run over the portal which may obstruct the filament guide tube.


While re-reading your post I noticed that I did not answer your question at the end, sorry. I used two aluminium connector pieces which are slit in spiral form to allow angular differences between the Z axis motor and the threaded rod for the movement. You can see them on the image above right above the Z axis motors. So far I have not noticed any problems with that. The coupling is a standard part that was included in the mechanics kit I ordered. Since the motor and the threaded rod only have a fixed position at the motor mount, the other is at the nut for lifting the X axis movement and that point continuously moves depending on where in height the X axis is at the moment. So I think there are not much hat can go wrong angle wise.

When it comes to the end stops, I have chosen them to be placed as follows:

 X axis - at the left hand side and the micr switch triggs against the stepper housing.

 Y axis - at the left smooth bar triggering against the left bearing housing under the board.

 Z axis - to the left, below the X axis motor mount triggering against the underside of the motor mount.

I have only used three micro switches so far but am thinking of using three more to definately define the both ends of the travel for all axis.

So far so good today.

/Peter

[PeterE]

Some more done this evening together with image no 100 in this build log    (Gosh so many pictures to no real use   

So, what's been done? Well nearly all cables had pre-mounted connectors so I started to fit each one to the RAMPS board. I found a useful assembly sketch here:  http://reprap.org/wiki/RAMPS_1.4#Wiring A description that even I understood! 

Started with the stepper cables in the centerline between the display cables. Next was the end stops then the tempsensor from the extruder. Last this time was the extruder heatsource (the two orange cables at the bottom of the RAMPS board.)
Still missing is the extruder fan connection as the cable length was too short and needs lengthening. Will remove that connector anyway as it will use the connection for extruder two (also meaning I can control on/off and runtime of the fan.) Finally the cables for the heatbed and its sensor, but I found the supply cables I bought is perhaps too stiff and after a rethink I will get some silicone cables instead.  These cables must be as soft as possible to not restrict the movement of the heatbed un-necessarily.

Also waiting for some heatsinks for the stepper controllers. Will use the standard ones now, but will look at changing if they seem to run hot.

When all that electrics are done and some minor mechanical bits in place, it will be time to switch the contraption on for the first time - duck and cover time 

/Peter

[picclock]

Hi PeterE

Good to see your latest pictures and progress. Like the idea of tucking all the electronics behind the gantry. I presume you already have a fan/shroud sorted for cooling.

I noticed that there does not appear to be any cable strain relief / support for the extruder/head/sensor cables. Because this assembly is likely to whizz back and forth a few thousand times the metal in the wire will become work hardened and fracture, normally at the point where the insulation stops. It might be an idea for the cables in the spiroband to be clamped using a P clip or similar. One of the motor mounting bolts, or somewhere else nearby will do. That way the bend radius during movement will be much reduced and the cable will be supported by its insulation.

Looking really good so far. Keep up the good work.

Best Regards

picclock

 

   

[PeterE]

Thanks picclock!

A fan for the electronics is definately on the list, and a shroud to control the fan air stream too. Just haven't worked out placing and air flow directions just yet... 

The strain relief is going in, still to do, thanks for your ideas, will take those into account.

Also managed as smallish bit today. Changed the power feed cables for the heatbed from car audio quality to silicone quality. The silicone ones are at least three times as smooth and bendy as the car audio ones. I'll show the fitting of those in the next image series in a couple of days.

BR

/Peter

[PeterE]

Good Evening again,

Some more done tonight before some coffea and a short TV break interfered.

Added heatsinks to the drivers, connected the extruder fan and the heatbed thermistor. That means that all the electrics is done so now the look from rear is as below:

I made a partition between the PSU and the buildplate from a piece of plexi laying around. It does not show that clear on the image, but it is to protect the buildplate from air flow from the driver cooling fan that seems to be necessary.

So one of the last pictures from the rear of my printer. Here the plexi partition shows better. No risk that any cable is tangled up in a build.

Looking closely it is also possible to see how I placed the cables from the heatbed. They are first of all clamped to the underside of the buildplate and then a similar clamp at the base of the portal. The cables form a "U" with the opening towards the back. That should make the connection flexible enough to avoid un-neccessary breakages.

Over all the build kind of looks almost tidy in spite of being a DIY build.

Then turning the printer around to get a shot from the front.

Here I have placed the glass plate on teh heatbed and secured it using four paper clips. Works a treat! So, the remaining things to do is to make and fit a couple of cable clamps for the extruder cables and the X-movement cables.

That will finalize the mexchanical and electrical work. What still is missing is a holder of some sort for the roll of filament. That is something I intend to get at tomorrow.

All in all, it is closing in on the exiting first time run. It may happen during the weekend depending on what is planned by the rest of the family. My "little girl" - the now 25 years old school teacher - has finally found a place of her own (apartments are very scarce in Gothenburg these days) which may require me to do some "supporting activities". We will see.

/Peter

[BillTodd]

Watching with interest here Can't wait to see the first parts (she's 25 - she can move herself ;-))

What sort of current  do those little stepper drivers supply ? 

[PeterE]

Hi Bill,

The first bits will probably appear either tomorrow or during next week. Have to finish the filament roll carrier first.

Sure she would most certainly fix the move herself, but don't tell her mother .... (because she would totally and with emphasis disagree)  I was asked to support with some internal decoration jobs as some of the work that was done by a "craftsman" is really not up to any standard    I will take a couple of pictures when we get full access.  The immediate stuff is to add some trimmings between floor and wall in the  closet.

Up to about 2A but then they get really hot! I think picclock is a better person to ask that question as he has already measured that if I remember correctly.

BR

/Peter

[PeterE]

Sorry, no switch on this evening.

The rig for the filament bobin (roll) took a little longer than expected. It was one of those design as you go cases, and I had to do some pre-calculations to get it about right. Then it also needed some finish of course.

The filament carrier is in place.

The bracket fixing the carrier to the portal has a connector for the PTFE filament tube so the tube is secured in both ends.

I decided to give the carrier a bit of "design" as I wanted it to support and guide the roll to not fall off sideways.

It's all made of MDF this time, it does not need to be that strong.

On with the roll and thread the filament through the tube down to the extruder.

The filament is pulled out from the underside of the roll. I thought that would be the best as the angle towards the filament guide.

The roll stands on four simple ball bearings of skateboard type 8x22x7mm (IDxODxW). They are fitted to a shaft specially made for this purpose from material that was at hand. The brackets used are simple alu sheet items.

So the "fighting face" of the printer is done and now I can concentrate on getting the electronics to work.



Upcoming week will be interesting.

/Peter

[PeterE]

Sorry, no pictures today.

Have spent a few days reading up on the setup and calibration processes. I am still following the instructions here: http://www.dragonflydiy.com/2010/10/building-prusa-i3-printer-testing-and.html as they turned out to be very good - for me at least.

So, I have assembled a little too much and have to unplug the stuff from the electronics board to do it properly. No harm done, I just see it as a test fit. The stepper drivers are supposed to be set to 0.40 to 0.45V DC at the trim potentiometer. That should obviously deliver around 1A to the motors and that should be enough according to the description. Driver temp etc should be in a good range.

When that is done each movement must be set up with end stops and all. First X, then Y, and finally Z. Following on with the extruder filament feed rate and the hotend temp control. The last thing will be the heatbed and its temp control.

I will split this into several days work due to other evening activities of varaious sorts.

/Peter

PS
At the end I want to make sure you don't get me wrong about the comment on my wife above. She really is a sweet and helpful person only wanting to help as far as she can. And in cases like the move of her youngest she just goes into overdrive in trying to help. So, my work here is actually more to calm her down a bit.  I find it hard to describe this in a foreign language as my mother tongue is Swedish so I hope you bear with me.

[PeterE]

OK, printer switched on for the first time ever and nothing blew up 

But, there were no measuring points at the specified position on the driver boards to set the voltage. The voltage of about 0.4V shall obviously be about equal to half the output current which is supposed to be 1 A or so. Since I couldn't measure I made the assumption that the trimmer is linear and with the wiper at half-way point I would arrive at that setting as well. I can always trim that later if needed.

Connected the X movement motor and end stop as per instruction and there were still no surprises. The electronics does not react though.  Connected the PC to the arduino board through the USB interface and started up the Pronterface application to set the movement. It connected to the printer nicely as expected and read a series of values like it should, but then ... an "Error=0" appeared obviously interrupting and stopping the startup sequence.    What on earth is an error=0   

 Time to go through error messages .... 

But all in all it seems to start working slowly, we will see.

/Peter