My Journey to Build a Prusa i3

Hello, RepRap forums!

I have wanted a 3D printer of my own for quite some time now, but they aren't really in my reach since I'm just a teenager working minimum wage. So I decided I was going to start building my own reprap, and buy the parts a few at a time to save money.

I started off on the wiki to look for what I wanted to build, and I ended up choosing the Prusa i3 Box Frame. Then, I compiled a shopping list of parts and their prices. As of writing this, I have just finished the box frame and I'm looking at buying some parts from my list. For printed parts, I plan on using a Makerbot Replicator that my school has (it's free). My toolset is pretty limited at home, but I managed to get that frame together OK (I think). Pics

My shopping list is based entirely off of the Prusa i3 buyer's guide from the wiki here, but I know that it isn't perfect so I wanted to post it here for verification before I start buying expensive things. I have the frame assembled. Would the next step be to purchase the smooth/threaded rods and see if they fit into the calibration part (generated from the openSCAD file with all the right configurations)?
Here is my list: [docs.google.com]

Hey, welcome to the forum. I got my i3-alike running earlier this year and I've been really enjoying it.

A few thoughts on your parts list...

A lot of the prices seem a little high. If you don't mind the longer shipping times (4 to 6 weeks) you can often get better prices on Aliexpress. Most of the parts for my build came from there and I haven't had any bad experiences yet.

I used a mk8 combined extruder/hotend. They're cheap and work well for 1.75mm filament. I don't know how hard it would be to make it fit on a standard i3 carriage as I made my own. There's a pretty big variation in price on Aliexpress, I bought one of the cheaper ones, but when I bought a second one recently I noticed they had used some cheaper cheaper components on it. It works fine though...
[www.aliexpress.com]

Using lead screws for Z is a worthwhile investment, for example I used these (but check what length you need for your build)
[www.aliexpress.com]

Similarly, it's worth having the LCD to go with the ramps
[www.aliexpress.com]

You don't have to use borosilicate glass, I've been using an ikea mirror tile that I rescued from redocorating. Might be worth checking the dollar store and see if they have anything.

For end stops, three is enough (although there is some argument for fitting all six). I like the opto ones
[www.aliexpress.com]

Have fun!

Don't forget screws those things add up if you have to buy them at the hardware store. I would order a bunch from banggood.com or aliexpress. You should check prices for the other parts on those sites too like James said. Make sure you have an old PCU that can supply enough power on the 12V rail. I just bought a 430 watt one today from Microcenter for 20 bucks that says it supplies 32 amps on the 12V rail. There were some with higher wattage total that had less current on the 12V rail.

I agree a old picture frame glass or 2 dollar sheet from the big box store is good enough save the money and buy lead screws instead of all thread.

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Newbie with Folgertech 2020 i3.

If you are in the USA Ace hardware has a wonderful selection of m3 and m4 threaded parts.

My Replikeo did not have a spring loaded heat bed so I went to ACE and added the springs and screws to do this.

Edited 1 time(s). Last edit at 02/14/2016 12:38AM by Giantkiller.

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Replikeo Prusa I3 Rework, Ramps 1.4, Marlin, Pronterface, Tinkercad.
Plan B is always to be somebody else.

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JamesK
Hey, welcome to the forum. I got my i3-alike running earlier this year and I've been really enjoying it.

A few thoughts on your parts list...

A lot of the prices seem a little high. If you don't mind the longer shipping times (4 to 6 weeks) you can often get better prices on Aliexpress. Most of the parts for my build came from there and I haven't had any bad experiences yet.

Thanks for the tip! I hadn't thought to go to Aliexpress yet. Also thanks for all the links, I'll be using those. Saving money is good.

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msaeger
Don't forget screws those things add up if you have to buy them at the hardware store. I would order a bunch from banggood.com or aliexpress. You should check prices for the other parts on those sites too like James said. Make sure you have an old PCU that can supply enough power on the 12V rail. I just bought a 430 watt one today from Microcenter for 20 bucks that says it supplies 32 amps on the 12V rail. There were some with higher wattage total that had less current on the 12V rail.

I agree a old picture frame glass or 2 dollar sheet from the big box store is good enough save the money and buy lead screws instead of all thread.

Darn, I've already bought most of my M4 screws from Lowe's. I'll make sure to buy my M3s in bulk online. Also I was on IRC and they said that it is super important to get precision threaded rods, especially for the Z axis. Also, I have a PCU from an old PC. It has 280 watts and 16 amps on the 12 volt rail. Is that enough?

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Giantkiller
If you are in the USA Ace hardware has a wonderful selection of m3 and m4 threaded parts.

My Replikeo did not have a spring loaded heat bed so I went to ACE and added the springs and screws to do this.

I have an ACE pretty close to me, I'll go check out what they have there. Lowe's selection of threaded parts was pretty ok, but they did not have winged bolts.

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jandcando
I have a PCU from an old PC. It has 280 watts and 16 amps on the 12 volt rail. Is that enough?

I have been reading 20 but I don't really know for sure. I had several old ones too but none that claimed 20A on the 12V rail so I just bought a new one. 20 bucks for one that can do 32A and is silent even under load was a good deal.

Oh and if you decide to remove the extra wires don't be dumb like me and forget to leave a 5V set. I was planning on keeping one 5V set in case I ever want auto bed leveling and forgot.

Edited 1 time(s). Last edit at 02/15/2016 12:09AM by msaeger.

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Newbie with Folgertech 2020 i3.

If you are using a pcb heated bed for the i3 that draws up to 13a. A heater cartridge at 40w is 3.5ish amps, other motors a few amps. 20amps is about the lowest I would consider. Watch your temperatures on the power supply and you should be fine.

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Prusa i3 Rework - Ramps 1.4 - E3d Lite6 - Full Graphic LCD Controller

Some (older) PC PSU's need load on 5V too. If I disconnect my Raspberry Pi from 5V line of my bench power supply which is old PC PSU, I get something between 1.5 and 16 volts with awful ripple. But Raspberry loading the 5V line I'm 12.2V with any load. There are some fans running from 5VSB too, but I don't those take much current.

Anyway remember load the 5V line so that 12V line doesn't go too high and break stuff.

Yep. I forgot that. Stick a 100k resistor from 5v red to ground black.

Or a 330 ohm in series with an LED. Cool power on indicator.

Edited 2 time(s). Last edit at 02/15/2016 07:58PM by Giantkiller.

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msaeger

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jandcando
I have a PCU from an old PC. It has 280 watts and 16 amps on the 12 volt rail. Is that enough?

I have been reading 20 but I don't really know for sure. I had several old ones too but none that claimed 20A on the 12V rail so I just bought a new one. 20 bucks for one that can do 32A and is silent even under load was a good deal.

Oh and if you decide to remove the extra wires don't be dumb like me and forget to leave a 5V set. I was planning on keeping one 5V set in case I ever want auto bed leveling and forgot.

Bundle all wires up to one of each. Red, Yellow, Black.

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Giantkiller
Yep. I forgot that. Stick a 100k resistor from 5v red to ground black.

Or a 330 ohm in series with an LED. Cool power on indicator.

That's not going to draw enough current to balance the regulation. If you have an old car headlight bulb where the dipped beam filament is blown but the main beam is still good, that's not a bad starting point. You're looking to draw several amps on the 5v line, so if you wanted to use resistors you'd be looking at something less than 1 Ohm rated for 50W or more and mounted on a suitable heat-sink.

Thank you for all the electrical help, guys. I'll go look for a power supply with more amps.

On another note, what "carriage_l_base" setting should I use in the configuration.scad file if I want to have a mk8 combined extruder/hotend? This is the text in the config file:

// Select carriage lenght ******************************************************
// 30 for single carriage extruder (two holes with centers 30mm apart)
// 50 for wade or single with fan (three holes, 30-20)
// 80 for full length carriage (four holes, 30-20-30)

carriage_l_base = 50;

I'm not really sure what I need to do to attach the mk8 assembly to the carriage. Is this setting even anything I should worry about?

I'm not familiar with the standard Prusa parts, but I suspect you might need a different carriage entirely for the mk8. I looked on Thingiiverse and found this.

[www.thingiverse.com]

No idea if it's any good, but it might give you an idea of one approach. My carriage is made out of aluminium angle, and I hold the mk8 in place with a single screw through the bottom - the same screw goes up inside the spring of the tension lever. It's roughly 18mm between centres of the heat break and the securing screw.

I'm having a rough time looking for a good controller to buy... I've gone from shopping for a RAMPS 1.4 to a Smoothieboard to Melzi to Azteeg. I think that Azteeg might give the most value for its price, but I could be wrong. [www.panucatt.com] . I'm all over the place right now, I think I need sleep.

On the bright side, I got OctoPrint working on my Raspberry Pi. No printer to connect to yet, though.

That's a really nice looking board, but it's a bit limited on expansion for the $$$. On the other hand, chances are you can make an expansion board to connect to spare pins if needed. I liked mega2560 and ramps for my first build - with the individual parts being cheap and modular there was never too much worry about breaking anything while I was repeatedly taking things apart and putting them back together. Getting started with ramps and swapping to a high end board later doesn't seem like a bad approach, unless you're uncomfortable adjusting the Vref pots on the drivers.

I've been shopping for power supplies and I think I've settled for this one: [www.amazon.com]

It has lots more watts than I'll need, but it was literally the only one that could put out more than 20 amps on the 12-volt line. This will most certainly do the job, but if anyone can point out a cheaper option I'm all ears.

You might want to check around and see if anyone you know has an old pc that isn't being used and they are thinking of throwing away. A lot of the older power supplies with dual 12v rails work well.

If I didn't have spare PC psu's lying around, it would be a hard choice between spending money on a pc supply or getting a dedicated 12v psu. There are some nice points about having software control of the 12v, but it's a lot of work to make a PC psu into a tidy printer power supply.

Edited 1 time(s). Last edit at 02/17/2016 07:18AM by JamesK.

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JamesK
You might want to check around and see if anyone you know has an old pc that isn't being used and they are thinking of throwing away. A lot of the older power supplies with dual 12v rails work well.

If I didn't have spare PC psu's lying around, it would be a hard choice between spending money on a pc supply or getting a dedicated 12v psu. There are some nice points about having software control of the 12v, but it's a lot of work to make a PC psu into a tidy printer power supply.

About the dual 12v rails... How does that work? Can I combine the wires to get more current if neither of them go over 20 amps on their own?

I've wondered the same thing - I don't know exactly how the dual rail system is set up. For a typical 200mm² setup it's not an issue. Use whichever of the rails has the highest rating just for the heat bed, and the other rail for everything else. The pcb heatbeds usually draw around 10Amps at 12V, so if the rail is rated for 15A or better you should be good. That's a fairly common rating for old 450W psus. Without a load on the 5V line the 12V will droop under load though - that's one of the annoyances of using a PC supply. There are instructions available for reworking the PSU to regulate just on the 12V line that I want to look into someday, but for now I use a headlight bulb on the 5V line, which keeps the 12V line between 12 and 12.4 volts.

I actually have more than one power supply laying around. None of them have enough amps to run the printer on their own, but is there a way I could use one PSU just for the heated bed and another one just for the rest of the printer? I don't really know how the wiring works here or if the type of board I'm getting matters (I plan on getting an Azteeg x5 mini), so sorry if this is a stupid question. I really don't want to spend more money than I need to.

So in principle, as long as the PSUs can tolerate having their grounds connected then you could use them together. However, given the amount of effort it takes to get one PC supply working nicely for 3d printing, I wouldn't recommend trying to use two.

Ok I just ordered a E3D v6 hot end. I'm waiting for the Smoothieboards to be back in stock, and that is really what is holding me back right now. I bought a wood sheet of higher quality from ACE, and I'm going to use it to make a new frame. One that is painted and sealed to look nice. Only problem is that I don't have any power tools to cut the wood with, only a handsaw. Anybody know if Lowe's can cut wood that you bring in yourself? If not, I think some of my friends have access to something I could use...

If the Smoothieboard is out of stock, have you considered the Duet? Like the Smoothieboard it is 32 bit with configuration of the motor currents done in software and all configuration done in a file on the SD card. But the firmware supports a much better web interface than the Smoothieboard including fast file upload to the SD card, also it supports extruder pressure advance.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

for psu you can use a xbox 360 psu

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Check my rubbish blog for my prusa i3

up and running
[3dimetech.blogspot.co.uk]

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dc42
If the Smoothieboard is out of stock, have you considered the Duet? Like the Smoothieboard it is 32 bit with configuration of the motor currents done in software and all configuration done in a file on the SD card. But the firmware supports a much better web interface than the Smoothieboard including fast file upload to the SD card, also it supports extruder pressure advance.

I haven't heard of the Duet. I'll look into it!

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chris33
for psu you can use a xbox 360 psu

I don't have an xbox Thanks for the info though! Maybe I can track down a friend who has one.

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dc42
If the Smoothieboard is out of stock, have you considered the Duet? Like the Smoothieboard it is 32 bit with configuration of the motor currents done in software and all configuration done in a file on the SD card. But the firmware supports a much better web interface than the Smoothieboard including fast file upload to the SD card, also it supports extruder pressure advance.

It would appear that those are out of stock as well, at least from the official site. It looks like a great board, though! I'll keep tabs on both boards and see which one comes back in stock. I happen to know from IRC that the Smoothieboards will be back in stock in a couple weeks now. I'll really buy either one, but the Duet's price is very attractive. I'm going to research both options a bit more now.

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jandcando

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dc42
If the Smoothieboard is out of stock, have you considered the Duet? Like the Smoothieboard it is 32 bit with configuration of the motor currents done in software and all configuration done in a file on the SD card. But the firmware supports a much better web interface than the Smoothieboard including fast file upload to the SD card, also it supports extruder pressure advance.

It would appear that those are out of stock as well, at least from the official site. It looks like a great board, though! I'll keep tabs on both boards and see which one comes back in stock. I happen to know from IRC that the Smoothieboards will be back in stock in a couple weeks now. I'll really buy either one, but the Duet's price is very attractive. I'm going to research both options a bit more now.

Which part of the world are you in? T3P3 in the UK seem to be out of stock of the Duet, but Filastruder in the USA appears to have stock.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

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dc42

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jandcando

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dc42
If the Smoothieboard is out of stock, have you considered the Duet? Like the Smoothieboard it is 32 bit with configuration of the motor currents done in software and all configuration done in a file on the SD card. But the firmware supports a much better web interface than the Smoothieboard including fast file upload to the SD card, also it supports extruder pressure advance.

It would appear that those are out of stock as well, at least from the official site. It looks like a great board, though! I'll keep tabs on both boards and see which one comes back in stock. I happen to know from IRC that the Smoothieboards will be back in stock in a couple weeks now. I'll really buy either one, but the Duet's price is very attractive. I'm going to research both options a bit more now.

Which part of the world are you in? T3P3 in the UK seem to be out of stock of the Duet, but Filastruder in the USA appears to have stock.

Forgive me for my ignorance, I didn't know of any other sellers. Thanks for pointing me to that one, I'll be ordering a Duet soon!

I could use some assistance on making my wooden frame... I've already made two of them, but the first one is made out of crappy wood and the second one's pieces aren't cut straight. How OCD do I have to be about making this? I feel like I should make a third one to be extra sure that it will be ok. The first frame I made was from a very large sheet of low-quality plywood I got a Lowe's. They cut it for me with their super fancy saw thingy and each piece was perfectly sized and straight. The only problem was all the holes and missing filling in the plywood. I went to the store again and got a better sheet of wood: a 4 ft by 4 ft sheet of birch plywood. I don't have any power tools at home for cutting wood, so I'm relying on friends to get my pieces cut. My friend helped me out, but he used a handheld reciprocating saw and the cuts were far from perfect. So when I built the new frame it was all crooked and I was unhappy with the overall construction.

Should I use a different sort of wood? What tool is best suited for making long, straight cuts in wood? I'm terribly sorry if these questions are downright stupid, but I haven't really been exposed to carpentry in general so far.