Modding Project: Prometheus (DIY 3D Printer)-August 21, 2011- Replication!

Thanks, to answer your question; it really depends on the availability of materials and how much you plan on salvaging or buying. The biggest factor in price though is sourcing the parts that are rapid-prototyped, to have them commercially printed can cost a fortune (the material cost alone for the Dimension BST I used ran around $300. But a RepRap can print the same parts out for a fraction of the cost. All in all though the price range varies from $400-$1,000 USD. I have not really kept track myself; I would imagine I have spent around $500-$600 range (excluding the cost of my rapid prototype parts), and I did not salvage anything.

 

I dont know, i really dont like the design at all, its just not well executed, its WAY overcomplicated which makes it fragile and difficult to assemble, number of parts is a joke honestly, it has now more parts than my big cnc which is easily ten time more accurate and atleast twenty times bigger, dont get the concept, at all.
But maybe u just have to make tradeoffs if ure going for as cheap as possible and replicable by itself.

 

I completely agree with you on the idea of it being over-engineered. I mean the dang thing uses 12 bearings just to constrain the Y-axis. You are correct in your assumption that there are trade offs for it being able to self replicate. The idea behind the current design is that most of the parts can be found a local hardware and electronics stores. Really the only semi-unique parts to it: are the drive belt, motor controllers, motors, and ATmega chip. The rest of the parts are readily available from any hardware/hobby store.

Its design has been the topic of much discussion and many have been working on revisions that drastically reduce the parts count while retaining its ability to self replicate. I hope to contribute to that cause when I finish my printer. Others though have decided to branch off with revisions that completely rely on extruded aluminum designs, and their parts count is drastically lower. However in the off chance that they bend or break something they have to wait to order new parts, where as others just make a trip to the local hardware store.

Still though it is surprisingly sturdy and I don't imagine that it has many fragile bits to break. The only part I am worried about is the extruder barrel due to the high heat. I would be careful about making claims about accuracy. I have no idea how accurate mine is as I have not printed anything yet, but some report to have reached .00125". So 10x that would be on the order of single digit microns, which your machine may very well be capable of. I doubt I will achieve anything near that for my first printer, but I would still be happy if I could measure my accuracy in the .02-.01" range after some tweaking.

As to why anyone would ever use a 3D printer instead of your awesome CNC project, take a look at my response to Rocket733's post. Really they each fill a specific role.

 

I remember talking to a computer science professor about 3d printing, he was all enthusiastic about how to integrate computers into toys and into schools. He thought that in 10 years schools would have 3d printers and kids could design and print stuff using them.

Anyway really cool stuff, Think how much easier it will be to make custom pump tops.

 

Wiring up the electronics, and keeping them cool.

February 4, 2011

Time for a series of major updates. I was swamped by school, and up until recently I haven't had time to write up a proper update. I was able to work on my printer here and there and remembered to take pictures along the way (mostly). So here is what I have been up to.

First up: Electronics!

So when I left off I had the X,Y, and Z-axes assembled and ready to go. Needless to say I was pretty excited about that and decided to get working on the electronics so that I could get things moving. First up was a circuit board for all of my stepper drivers. Off I went to the local hackerspace to get a PCB made for my printer. I created my own PCB that used sockets for my stepper drivers. That way, I would be able to easily replace driver boards should I somehow manage to fry something.


Then it was back off to my lair to solder the thing together. I wanted my circuitry to be easy to alter and upgrade so I opted to use pin headers and sockets wherever possible.


A brief description of the board layout: Power is provided via a standard 4 pin molex connector from a computer power supply. The 4 pin strips next to each socket are the pin headers for each motor (X, Y, Z-axes, and extruder). The 12 pin strip along the right side is for motor control. Each driver chip has data lines for enable, step, and direction. In hind sight I could have just tied the enable pins to ground as they are active low. Since I wouldn't have a reason to disable the motors while the system is on. The 4x6 grid of pins is for the end-stops, more on those later.


Complete board with drivers installed.


Those driver chips can get quite hot, and while they have thermal protection circuitry, they need some cooling. Luckily I have a bin full of old heatsinks that I have salvaged over the years. The donor for this project was an old Abit GF4 video card.


Unfortunately it was a little too big for my application... which was easy to fix


After a quick run through my scroll saw I was ready to go, but it was such a shame to leave it all scraped up.


I knew that it was completely unnecessary to lap this heatsink, but just for the nostalgia I decided to go ahead and polish it to a mirror finish


All of the control circuitry is handled by an Atmega 644P with a variation on the Arduino bootloader burned onto it. Data is fed to the ship over a FTDI USB->232 chip.


Assembled and ready to go.


After that it was time to assemble the end-stops. The end-stops allow the machine to accurately home to the same position repeatedly, while also preventing the printer from plowing into itself while operating. These end-stops are based on optoswitches.


The minimum end-stops assembled.


Hotel keys make for great flags to trigger the optoswitch.


On to making the jumpers for the motors.


I realized that I needed a breakout board for my Atmega, so I used a scrap of protoboard that I had lying around.


It may not be pretty, but it's all wired up. I will get around to cleaning up the wiring later.

 

Wiring the extruder, and running the first few prints.

February 5, 2011

Here is the next installment in my series of updates.

After wiring up my electronics, I was very excited to try to print something, but first I had to add on a core component to the printer, the extruder.

The extruder is an interesting piece of hardware; not only is it probably the most crucial part of the whole printer, but it is also the part that requires the most fabrication and assembly. In an earlier post I explained how it works, but now I tackle the challenge of going from theory to application. First challenge, the heater barrel will get HOT; in some cases the heater has been reported to be forced out from the Teflon tube while the extruder is running. So I need to fabricate some sort of retention mechanism that will hold the heater barrel in place. I soon found my answer in the form of a salvaged snap ring and a scrap of aluminum I had lying around.

Extruder assembly bolted in place, and snap ring installed. The snap ring will give me a surface for the retention mechanism to press against.


The aluminum ring serves a couple of purposes:
1-It allows me to hold the heater barrel in place.
2-It acts as a small heatsink to help keep the Teflon from getting too hot.
An OLD floppy drive (5.25") was the donor for the aluminum.


A piece of acrylic allows me to transfer the load from the barrel -> aluminum ring -> acrylic -> X-carriage assembly.


It is starting to come together.


Here it is, installed, all wired up, and ready to go. Unfortunately I neglected to take pictures of the heater with out the insulation. The heater itself consists of the copper core, with a 10" length of fiberglass insulated nichrome wire wrapped around it. I then wrapped a small length of ceramic fiber tape around the nichrome windings to help insulate them. To top it all off I added several layers of high temperature kapton tape. Above the heater element I installed a small thermistor to monitor the temperature of the heater (a thermistor is a resistor that changes its value based on temperature).


It is ready to do some printing.


The printer works by having a host computer slice up .stl files (3 dimensional models of the object to be printed) into horizontal layers of a specified height. The computer then processes those layer slices into a series of commands that controls the printers movement (g-code). This g-code is compiled together and saved for future use. I then take the g-code and stream it to my printer over a USB port with the aid of some host software that allows me to monitor the progress of a print and gives me direct control of the printer. I proceeded to burn the g-code interpreter onto my Atmega, and pick out some models to print.

The first few prints were just simple calibration prints to help me begin the long process of configuring the printer. After amassing a pile of plastic that was supposed to resemble single walled boxes I finally got something resembling the model. After that I went on to make a bunch of small boxes 20mm x 20mm x 10mm to test the infill. After several hours I felt confident enough to print something beyond boxes.

My friend suggested that I print a Rilakkuma (some sort of bear). I have no idea what its significance is, but he recognized it immediately when we were browsing through .stl files on Thingiverse. All I remember is him saying something about how he saw them while living in Japan. The other print is something I think many of us are familiar with, a weighted companion cube from Portal.


This cube measures approximately 1"x1"x1". It is a real mess, but I must say that I was rather proud of that moment. I still had a long way to go, but it was really neat to hold it and think that I had printed it on a 3D printer that I had built.

 

Hey! You got it working. The potential for incredible stuff is there. Obviously it would work better making 'organic' objects. The cube is to mechanical and shows of the resolution issues.

Ramble translation: Print out a bucky ball, or a hollow spiral-wrapped sphere.

 

a big thumbsup from me, i remember my first parts, they where heaps worse, trust me
But i also remember taking them from the machining bed and going apeshit cuz of happiness

 

Thanks for the support! Lenne I may have to pick your brain on linear rails and ballscrews as the CNC bug has me so bad that I want to build a printer with a LARGE print volume.

I have a lot more to post, but I have a couple of tests to take this week.

 

Building an enclosure for the printer.

February 12, 2011

Now that school testing is out of the way (at least for the next few weeks), I can get back to updating this log. After tweaking the print parameters a bit, I realized that some of my problems were caused by the uneven temperatures of the build environment. By keeping my printer in an open space it was subject to the ambient airflow in the room. This caused my prints to cool unevenly and left bad warping. It also caused a problem where if the ambient air was too cold, the filament would not fuse properly to the layers below it. This meant that prints were weak along a horizontal plane and could easily be sheared along the layers.

In order to resolve this issue I decided to build a closed print envelope (IE: a box). I hoped that such an enclosure would help regulate the temperatures inside. In theory this would ensure that the prints cooled at an even rate, and would keep the cold air spilling off the windowsill from messing up my prints.

I quickly sketched out designs for a box made from 2x2s and Masonite. After a quick trip to the hardware store I was ready to go.

Attack of the blurry-cam!


Masked, marked, and ready to cut.


I pulled out the sawhorses to cut the wood, but much to my dismay I found we only had 2 support clips. I knew I could just balance the wood carefully and then cut it, but where is the fun in that when you have the ability to make what you need.

I measured the existing clips and made copies in Inventor. Then I fired up my printer to make the extra clips.


The first one came out better than I had anticipated, but there was still quite a few "stringers" and it was pretty rough in a few places.


Unfortunately the printer locked up about 2/3rd's of the way through the 2nd clip and shut down. Those random lockups would be an issue that perplexed me for many weeks to come. On the bright side, the print was far enough along that it was still usable and also offered an opportunity to examine the infill pattern of the prints.

After a little cleanup they looked promising. I decided that the retention tabs were worthless and chopped them off with my dremel


It was time to pull out the clamps, glue, and nails. l quickly assembled two of the side panels and set them aside to give the glue time to set and cure.


After a few hours the panels were ready to assemble. I test fit them to make sure that the parts I had cut thus far would work. In this picture I am setting the walls in place to get an idea of the finished appearance. But they are inverted, with the base pointed skyward right now.


Gluing two sides and completing the framing.


Adding the back panel.


Not quite done, but that should do for the time being.

 

Working on the enclosure some more, along with a few more prints

April 22, 2011

I have been tinkering with the printer on and off for quite awhile now and I am starting to get a better understanding of all the settings I can configure to enable me to get a better print. However manipulating them to form the proper combination will take some time. What you will see in this update is from a little while back but school has kept me busy enough that updating this log took a back seat to studying.

In the last update I had begun work on an enclosure for my printer that would help even out the temperature of the build envelope. Just that basic framework made a marked difference in the quality of my prints, and the results became much more repeatable. This allowed me to gain a better understanding for how each of the variables interacted with each other for configuring the printer. However there was still a lot of work to be done so that I could completely regulate the temperature of the build envelope.

First up, putting a bottom on the enclosure. I had made the walls and top as one large removable piece, but it still had yet to make the bottom of the box, or a window/cover for the front opening. I didn't want the box top to slide around and potentially bump the printer so I needed a way to constrain the box lid so that it would stay in one position.

Lucky for me I happen to have a 3D printer now It isn't complete but it is at the point where I can use it to make the parts I need as I continue to work on this project. Time for pictures!

Its a crude setup, but it works. Eventually I will get around to building a computer to specifically run the printer.


I began by creating the model for some corner brackets that I would use to hold the box in place. After that it was a simple matter of exporting the .STL file and running that through a slicing program that converts the model into g-code.


Then I proceeded to print out the first of four brackets.


The part came out ok, but there was a lot of "stringers" and random ooze that had to be trimmed off with a utility knife. Definitely not perfect, but they will work well enough for their task.


About an hour later I had 4 brackets printed, cleaned up, and ready to install.


Here you can get an idea of what I have planned for them. They will each be used to brace one corner of the box from the inside. I will be screwing them down into a piece of particle board.


The screws I had were pretty thick so I pre-drilled the holes before mounting the corner brackets to avoid splitting the wood.


After that I needed to work on a window for the front of the enclosure. That way I could have more control over the temperature of the air inside of the enclosure. I had plenty of acrylic lying around so I cut a piece to size and then set about the task of making brackets to hold the window in place, yet still allow me to quickly remove the acrylic to access the printer.


It occurred to me that the plastic might scratch up the acrylic over time so I used some adhesive backed felt to help pad the clips.


Once installed they worked like a charm. Amazingly enough the box has enough of a seal from just resting on the base that the window does not fall out. I doubt that will last for long as I have to cut some access groves for wiring and filament, but to me this is rather remarkable as I cut the panels using a scroll saw (hardly a recipe for perfectly straight cuts.)


I have also been trying to print out some more random parts and lately I have been on an EVE kick. I tried to print out some of the smaller ships from EVE with varying degrees of success. It was a good excuse to try out the support options of the model slicing software.

When printing a part with large overhangs and gaps it is necessary to print "support structure"; this serves as a temporary support lattice that holds up the model as it is printed. After the print is complete you can snap away the support structure and enjoy your model. Some commercial systems use multiple print heads and materials to enable soluble support structures that are dissolved in a mild chemical bath (Dimension systems use a solution of sodium hydroxide and water). The bath dissolves the support material and leaves the model intact. As I only have one print head I have to use breakaway support material.

Any guesses as to what this is?


I also printed out a small mushroom that should appear familiar to most everyone here. Note that the spaceship still has the support structure attached.


After breaking away the support material I had a Gallente shuttle from EVE online, alas the surface finish is poor. I have a long way to go with the firmware and file processing to achieve a smoother finish.


Since the printer struggles with arcs I thought I would try a more angular ship from EVE. Any guesses as to what this one is?


Make your guess and check my Album to see if you were right. I will update the log itself in a day or two to show the pictures in this post.

EDIT:
If you guessed a Caldari Destroyer, you were right!

 

That's pretty cool dude. I've been watching the rep-rap guys since the beginning. You're doing exactly what I'd use if for. "I need a what's-it to hold this in place." 20 to 30 minutes later I have a what's-it.

 

Back at it again

August 7th, 2011

Time to dust off this thread:

It has been more than a little while since I have posted an update; it seems that I can never get this log up to date with what is actually going on. Here is a glimpse of what has been going on.

Model files (.stl) are made up of triangles; these triangles stitch together to form the surface of the part that is to be printed. Depending on your export settings you can create a wide variety of models that correspond to different qualities of final product. Coarse models take less time to process but this also results in rough shapes; conversely, detailed models take a very long time to process before you can print them. Then you have the geometry of the model: Hard edges aren't much of a problem, but arcs are very susceptible to turning out grainy. To make matters more complicated, the program that processes these .stl files into a print also does some approximations of its own. Currently the software and firmware for these printers does not support G-code commands for performing arcs; so when you process an arc, you still end up with a shape made up of many small line segments.

These segments translate into vertices (wherever one segment ends and the next begins). For reasons previously indeterminable, my prints would pronounce these vertices even more than usual. I'll refer to these as: "vertex bumps"

These vertex bumps were especially prominent along large arcs.


It was later determined that these vertex bumps were caused by small processing delays in the firmware of the 3D printer's microcontroller. Newer firmware builds are now much more efficient and display much better surface quality than previous prints. With a few more tweaks to the temperature profiles of the printer, I have been able to nearly eliminate these bumps from my prints. Due to how much I have to add to this log, pictures of the latest prints will not be available for a few days.

Temperature control of the build environment continued to be an issue. While I had previously fabricated an enclosure to help keep the ambient temperature a bit more under check, it was not enough. The enclosure helped to resolve some issues, but also created others. It turned out that a certain amount of airflow around the print was necessary for a quality print. Without that airflow, my prints started to sag and warp due to not being able to cool enough between passes of the hot-end. At the same time I couldn't let the part cool too much, or else the next layer wouldn't fuse properly. The challenge was to devise some way to keep the build chamber warmer than the ambient temperature of the room, while at the same time cooling the print enough for each layer to properly solidify.

The enclosure was great for controlling the airflow within the build area, but the 1/4" masonite was a very poor insulation material. So another trip to the hardware store and I had some sheets of Styrofoam.


After a bit of measuring and cutting I was left with this.


I also took the opportunity to add a small hole and feed tube for my filament. I printed out the clamps that held the tubing in place after whipping them up in inventor. Alas this killed the seal on the box and now the acrylic window falls out on its own. I'll get around to making a retention clip for the window later.


In order to help the print cool and maintain a uniform temperature throughout the enclosure I added a pair of delta fans that I had lying around. Again, I created the needed mounting hardware in inventor and then printed out the needed parts.

Here is a screencap of the designed part along with the G-Code that would later be fed to the printer to make the part.


A about 30 min later, I had a pair of these parts ready to be installed.


While the first set of parts were printing, I had already designed and processed the rest of the files for the fan brackets. I started the prints for the brackets as soon as the previous print job was done, and then worked on a different project while I waited for them to finish. A bit later the fans were mounted and wired.


I would run the fans at 5v with the window in place during prints, after a print I would run the fans at 12v and remove the window to cool down the part before I removed it.

Between the fans, the insulation, and a newer firmware (still very old compared to what I am using now), I noticed a marked difference in print quality. Here are some photos of a 30mm fan that I designed: The first photo is an older print, followed by a more recent one.



It was time to try a more complex print. I must say that I was rather pleased with the result. This picture was taken less than a minute after the print was completed and I have done nothing to clean up the part.


As always, feel free to leave questions and comments.

 

Your miniature EVE ships are pretty neat. You should sell those.

 

Ok this doesn't look as bad as I thought it might.

My entire MSc has been on similar rapid prototyping machines and CNC type things

YGPM

 

Thanks for the comments. While CCP is completely cool with fans using their IP for personal use, they are not ok with people selling the materials for profit (not even for in game currency). Though I have thought about sending a few free ships out to some corp mates.

Since I have been really busy with work these past few days, I thought I would leave you with this video while I prepare the next update (I'll post it tomorrow from the hackerspace I attend).

I have been on a bit of an audio project kick as of late


EDIT: Massive meltdown making a new extruder

 

Awesome work!
Now I'm just thinking one thought; I need one of these in my life!
How much for a full set of printed parts?

 

wow!! just WOW!!!

 

Replication!

Again, thank you for the comments and questions. This next post should answer your question Journeyer.

August 21, 2011

I was hoping to have a bit more to add to this post, but it seems that it has (and will continue) to take longer than I had anticipated to get my printer back up and running due to the upcoming school year, work, etc. Anyways on with the post!

I have been waiting to post about this particular subject for awhile, but it wasn't until last Saturday that it was finally appropriate to do so.

Over the last year there has been a lot of development in the RepRap community. It seems as though every few weeks there is a new webstore or shop being setup to sell 3D printers to the hobbyist community. These shops are selling everything from misc parts for RepRaps (nuts, bolts, washers) to complete kits and even ready to use printers. It really is amazing to see how what started as such a small movement is really starting to pick up momentum and gain popularity.

Of notable interest is the development of the "Prusa Mendel". One of the members of the community took note of the over engineering of the original Mendel (many now refer to it as a "Sells Mendel") and took it upon himself to simplify the design. The result is the Prusa Mendel. The dimensions and build envelope of a Prusa are nearly identical to that of a Sells, but the parts count has dropped drastically (along with total cost). For example take a look at this set of parts I helped to print back in February for a local hackerspace.

Other than 2 missing parts for the extruder, this is a complete set of RP parts needed to assemble a Prusa Mendel 3D printer. Quite a reduction from the piles of parts that I used to make my 3D printer.


Keep in mind that these parts were printed back in the middle of February, and that the print quality has risen since then.


The new design makes use of printed bushings to constrain the movement of the printer. They work remarkably well and have helped reduce the bearing count down from 52 to 4! We also get rid of the complex belt loop for the Z-Axis. Though with the simplification we do gain the added cost of one more stepper motor, which is worthwhile considering the reduction in parts and complexity.



Giving credit where credit is due, I printed only 1/2 of the parts; while Bill a fellow owner of a RepRap printed the other 1/2 of the parts. The set was donated to a local hackerspace, so they could build their own 3D printer and then print more sets of parts for others.

We gave those parts to the hackerspace back at the end of February, but due to some ongoing projects and busy schedules it wasn't until recently that they were able to finally assemble it. So I held on to the pictures and waited for the right time to post them. That time is now, when I add this picture to the set:

This is the Transistor's newly completed 3D printer

No, that is not me in the picture; that would be Bill, making some tweaks and adjustments to the printer.

It was rather gratifying to see a functional 3D printer that was created using your own 3D printer.


Now to answer your question Journeyer. Printed parts are now sold all over the place in addition to auction sites such as Ebay. Prices vary depending on where you are but state side the average price is ~$100 + shipping. The cost of the rest of the parts is now in the $300-400 USD range. That means that it is now possible to build a 3D printer for ~$500. If you are handy with electronics, and shop around for parts you can cut that cost down to <$400. While some thrifty individuals have built complete 3D printers based on the Prusa design for less than $300!

I would recommend checking the link I supplied as a starting point for where to get parts. If you track down their IRC channel (#RepRap on freenode) you might be able to get a set of printed parts for even less from a local reprapper. If you can't track down anyone local, PM me and we can work out something (offer is extended to any BT member who can't find a good deal on parts near where they live).

EDIT: 8/24/2011 I fixed it Well at least the hardware is working again. But with the repairs/upgrades I really need to update the firmware.