3D-UPFITTERS Prusa i3 MK2 Enclosure Kit Instruction Manual

: June 3, 2024
: 3D UPFITTERS

Table of Contents

3D-UPFITTERS Prusa i3 MK2 Enclosure Kit
Before you Start
Don’t Panic If You See This
Identify Panels
Assemble Panels
Let Us Help
References
Read User Manual Online (PDF format)
Download This Manual (PDF format)

3D-UPFITTERS Prusa i3 MK2 Enclosure Kit

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Before you Start

Is This Manual for Your Kit?
This installation manual covers the R3 enclosure design for the Prusa i3 MK2/MK2S/MK3/ MK3S enclosure. If you have the Prusa MMU or Prusa Mini enclosures this is NOT the right manual.

Is your Prusa Customized?
If your printer is stock then no customization is needed. If you have customized the printer, you should examine any modifications to make sure they don’t block the panels. If part of one of the panels is blocked, you can use a laser or drill to customize one or more panels. This should be done before removing the plastic or paper covers on the acrylic panels. Cutting acrylic requires great care as the plastic is prone to crack if mishandled.

Preparing the Printer

Remove any filament from the hot end (will require heating the hot end) and remove the filament spool from the spool holder.
Turn the printer off and unplug the power cable from the printer’s power supply.

Don’t Panic If You See This

If you can’t see through the plastic, please don’t panic! What you’re seeing is just the plastic or paper protective covering. You, dear customer, are way too smart to think the plastic is flawed and then call and email us over and over again leaving increasingly irate messages on Christmas Day.
You see, when plastic sheets are manufactured they are covered by either a paper (brown colored) or plastic (white) covering to protect against scratches. Follow the directions below to remove the cover and discover the beautiful plastic underneath. But if, in some rare instance, the plastic arrives with a crack or scratch, either from manufacturing or shipping, we’ll of course replace it for free. To remove the covering from an acrylic panel, lay the panel flat on a table. Then peel up a corner of the covering and CAREFULLY and SLOWLY pull horizontally to the sheet to reduce the lateral forces that would bend the acrylic. Watch the Video!

https://www.3dupfitters.com/blogs/news/acrylic

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Everything You Wanted to Know About Screwing But Were Afraid to Ask

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Probably the most confusing thing about assembling this enclosure will be which fastener or screw to use. Luckily it’s pretty easy to figure out once you know the system. While the exact screw to use will be detailed in each section of the manual, you probably won’t need to refer to it once you know the secrets.
The most common screw is the 12mm hex cap head screws. The 12mm screws are long enough to attach things to the acrylic front, top, sides and back. Each section will describe exactly which screw to use, to read carefully and use the specified screw for the best results.
The actual length of the “long” screws to attach the fan and or filter will vary depending on the depth of the particular shipment of fans we happen to get that month. They won’t be hard to spot since they’ll be the longest thing in the bags.
Finally, and we can’t stress this enough:

Leave the screws a little loose until the end adjustment phase. During that process you’ll be hand-tightening until the screws are snug, but you can easily use so much force the plastic pieces or the acrylic crack. Please don’t be that guy.

Identify Panels

Before you start to assemble the kit, lay out all of the panels and identify which panel corresponds to the front, left, right, back, and top. Although the panels are labeled, it’s easy to get them mixed up once the covering is removed, and very rarely a panel can be mislabeled. This chart will help you keep them straight. Note the panels are shown as they appear if you are located on their corresponding sides, i.e. the right side is pictured as if you were standing on the right side of the enclosure, etc.

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Assemble Panels

The Front Door
Each of the corners on the enclosure will be held together by the connectors pictured below. There are only two versions L and R, which can be identified by the letters stamped on the inside. The diagonally opposite connectors are identical, i.e. Bottom Right is the same as Top Left. In all cases the surface of the connector with the cutout pattern faces front or back. Note the two pictures below show the inside of the front panel.
If the holes don’t seem to line up please check out this video!
https://www.3dupfitters.com/blogs/news/how-to-attach-corner-connectors

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The front door is designed so that the latch is on the left. Attach the corner connectors on the inside of the door frame using the provided cap head 12mm screws. The top of the connector should be flush with the top of the acrylic. Adjust the screws snugly, but not tight as you’ll adjust them later.
When you remove the front door, be sure to remember the orientation, i.e. which part of the door is the inside and outside. You’ll want to attach the door the same way it was taped. The reason is the laser cuts at a small angle, so if you insert the door backwards this can create interference making it difficult for the door to swing properly.
There is also a mid-panel corner connector to attach on the right side. Use a 12mm M4 screws.
Locate the magnetic latches and use the wood screws to attach them to the latch mounts. Hand tighten and make sure they’re secure, but do not over tighten or they may strip. The magnetic latch can be later adjusted front-toback to make sure the door is flush with the door frame.

Each latch mount is attached via three screws. Two M4 12mm cap heads are used to attach the latch mount to the side, while a 30mm cap head secures the latch mount to the door frame.
Attach the hinges to the outside of the door and door frame using M4 12mm screws and nuts. There will be some play in the hole size so that you can adjust the door to swing freely.

Attach the door knob by first inserting the square M4 nut into the slot. Use a 16mm cap head screw to attach the door.
Now that the latches are mounted it is time to connect the strike plates. Each plate comes with a squishy adhesive covering the same size of the plate. Carefully attach the adhesive side to the acrylic at the location of each latch. Then, adjust the width of the metal strike plate so that it is held on by the pressure of the two sides of the plate. The adhesive covering will keep the strike plate from scratching the acrylic.

You can adjust the way the door swings by using the magnetic latch to hold the left side of the door in place, and then placing the front on its side so the hinges are at the top and the latch at the bottom. Loosen the screws and adjust the position of the hinges so that there’s an even gap on all sides of the door. The door should open and close freely. If you have trouble getting the door to fit properly confirm that the door was attached in the same orientation it was in before you removed the tape.

Attach Left Side
The left panel is distinguishable by its small hole for a cable grommet, in addition to having “left side” written on it. Insert the grommet as pictured before attaching the front of the leftside to the door frame. This is for connecting a USB cable to the motherboard or to pass wires from LEDs to a power strip.

Assemble Back
The four corner connectors are mirror images of the front. On each side are “mid panel corner connectors”, which are basically simple Lshapes for added strength.

The large 60mm hole is either for the included fan by itself, an air filter (purchased separately)/fan combo, or it can be covered up by a plastic disk depending on how much air flow you want.
Note that the fan, either by itself or paired with a filter or vent is necessary to draw air over the power supply. This both heats up the air inside the enclosure AND cools down the power supply, which extends its life. Only use the circular disk (not included) to cover up the hole if you have moved the power supply outside of the enclosure, or if you simply don’t care about power supply longevity.

Confirm the direction of the fan by plugging it into a USB power supply before attaching the filter. The round label should be on the outside
The fan should be attached on the outside of the enclosure.
The fan should be oriented to pull air OUT of the enclosure.
Use the long screws included in the fan packet to attach the fan. The length of the screws may change depending on the depth of this particular shipment of fans.
The U-shaped hole is for the cable grommet and holder. This will allow you to remove the enclosure without having to unplug the cables!
The back should look like the illustration to the right when you’re finished.

Attach Right Side

The purpose of the vent on the right side is to bring cooler air to the power supply to increase its longevity under heavy use. With the fan and/or carbon filter in place cold air will be drawn in through the power supply, both cooling the power supply and heating the air as it enters. Even without a fan, the power supply is still cooler this way because one side is exposed to colder air.
The right side panel is a little tricky to configure because Prusa now has used two different sizes of power supply. The default layout is for silver power supply they’ve used for years. Just make sure the cutout in the vent is on the bottom half to fit around the small bump at the bottom 1/3 of the supply.
If, however, your power supply is black, you’ve got one of the new ones. In that case you’ll want to run its power supply cord through the black grommet in the back of the enclosure.

You’ll also notice a gap between the bottom of the power supply and the vent. This can be plugged with a “Prusa gap filler” piece, shown in white, which is included in the kit.

Attach Top
If you attach the top and there’s overhang in the back, then it’s attached backwards. Make sure the top is attached in the right direction so the slit is in the right place.

Before you tackle the top, now is a good time to install the cross beam that adds support to the top in case you want to put the spool holder on top. (See beam circled in red in the illustration to the right.) It should just slide into the slots as shown before you attach the top. If you don’t see slots at the top one of the sides is probably on upside down.

Note that until the top is connected security the beam may fall out of place. That’s fine, just put it back before tightening the mid-corner connectors. You’ll now want to attach the mid-corner connectors before actually attaching the top. With the beam in place, it’s time to remove the plastic covering on top. First lay the top on a flat surface as shown in the instruction video. https://www.3dupfitters.com/blogs/news/acrylic Be careful, as the area around the filament slit will crack if handled roughly.

The top has a front, back, and left to right. This is because it overhangs the front which is twice as thick. The right side of the filament slit is closer to the right edge than the left. Use access through the doors to attach the top of the enclosure using M4 12mm screws.

If the top has an overhang in the back it’s because that part of the top should be at the front.

Sealing Gaps
Once the enclosure is completely put together, it is time to make sure that each of the panels is held tightly to each adjoining panel. The connectors are designed with a small amount of play that allows you to make small adjustments for the perfect fit.

Loosen screws on the panel to move.
Push that panel into place. You may need a friend to hold it tightly in the right spot.
Re-tighten the screws to hold the panel. Only tighten enough to hold the pieces snuggly. DO NOT OVER-TIGHTEN! These parts are sturdy, but they’re still all made out of plastic.

Repeat the process, going around the enclosure looking to make sure all of the panels are flush to each other.
You’ll also want to make sure the front door swings smoothly. The easiest way to do this is to lay the enclosure on a towel on its side so that the hinges are at the top. Loosen the screws attaching the hinges to both the door and the door frame and use the magnetic latch to hold the door in the middle of the hole. Now tighten the screws again, and the door should swing freely.

Once the gaps are sealed, you can then position the enclosure. The biggest thing with the power supply is to get the vent in the right place. If you are using the silver power supply there isn’t much tolerance in the placement of the off/on switch and power cable plug, so you’ll have to get it close. This will make it easier to turn off and on and provide the best seal so that heat won’t escape.
Note: The image to the right is for the silver PSU. If you have a black PSU refer to the section on the Right Panel assembly.

Plugging Things In

There are a couple of things to plug in: the Prusa itself and the fan. The old style silver Power Supply Unit just plugs in through the vent. If, instead, you are using the newer black power supply then the power cable goes through the grommet in back.
We recommend getting a combination USB power supply strip, available just about anywhere. That way you can power both the printer and accessories from the same strip, AND turn everything off and on from outside the enclosure.

Spool Holder
Instructions for assembling the spool holder are available online. You can simply sit the spool holder on the top of the enclosure where the filament can fit into the slit. Of course, you are free to use whatever type of freestanding spool holder you wish; there are hundreds of designs available on Thingiverse.

Thermometer
The optional thermometer will let you know approximately what temperature it is inside the enclosure. It attaches to the left side of the door piece using the same hole as the top-most corner connector as shown. It comes with a longer screw to fit through everything.

Managing Enclosure Temperatures
WARNING: Printing PLA without the fan turned on may cause clogging.

There’s not much to a 3D printer enclosure. Although ours look fancy, functionally they’re not much different than putting a cardboard box over the printers since both designs are passively heated by the beds. How complicated can they be? This section will explain a little about how they work, and how to manage the temperatures to get quality prints while protecting your lungs.
We generally get two types of customers:

Those interested mostly in air quality.
Those interested mostly in print quality

Think Airflow, Not Fishtank
The problem is those two goals use two different techniques in terms of airflow. For the best air quality, we use the same design as industrial equipment, which uses airflow to manage air quality. Because of physics, the amount of air moving into the enclosure has to be equal to the air moving out of the enclosure. When the air moves out of the enclosure carrying volatile organic compounds it can then be vented to the outside or run through an air filter.
People often ask us if the enclosures are airtight and have a bottom. If your main concern is air quality then being airtight doesn’t buy you anything since the particles will just float out when you open the door. It’s only by maintaining a negative air pressure that the particles are reliably kept away from human operators, which means having openings for air to both enter and exit the enclosure. If the maximum internal temperature is the goal, then being airtight also doesn’t help since the main cause of heat loss is through conduction through the sides of the enclosure, not through small amounts of air loss. A bottom doesn’t help either since while heat doesn’t rise, hot air does, and thus almost all of the heat of an enclosure is at the top. A bottom is helpful, however, if your table is too small for the enclosure. Since airflow is key, all of our enclosures come with fans chosen for CFM ratings to match the cubic size of the enclosures. This ensures that for cool-loving filament types like PLA there’s enough airflow to keep the temperatures in the safe zone.

Room Temperature
Passively heated enclosures are completely dependent on the room temperature as a starting point. If you’re trying to print ABS in an unheated garage in the winter the temperature inside the enclosure is never going to get hot enough. The reason is the bed heater has only enough energy to increase temps from the baseline. If that baseline is 22C, then you’ve got a good chance of getting into the sweet spot. If the baseline is 13C, then you’ll be lucky to warm the interior of the enclosure hot enough to print materials such as ABS.

ABS and Nylon
You want the internal temperatures higher for filaments like ABS, which happens naturally because the recommended bed temperatures are much higher. With the fans turned on we shoot for internal temps between 35C and 40C for 3D printers that use E3D hot ends because E3D recommends that temp range to avoid clogging. Keeping the temperatures in that range it puts the least stress on the equipment and follows the manufacturer’s guidelines. This works great for people either interested mostly in air quality or those who are riskaverse and don’t want to take a chance of clogging their hot ends or decreasing the useful life of their printers.
More experienced 3D printer owners though, those for whom a clogged nozzle is a known risk, might want to run the temperatures higher for less chance warping of ABS parts or to print nylon. In those cases, you can turn off the fans or even print one of the vent covers and just not vent at all. For our internal print farm, we do the later on a couple of machines where the temperature when printing ABS gets as high as 46C. They’ve been running like that for years with no filament clogging. Even with no venting of the power supplies, we’ve never had a power supply fail either. Obviously, your mileage may vary, as it depends on a lot of variables such as filament quality and the quality of the power supply in that particular printer. If you’re looking for the highest temperature’s possible, try turning the bed heater on for an hour before you print.

Perfect Enclosure Printing with PLA
Since PLA is perfectly happy at room temperature, the only reason to enclose it is for improved indoor air quality. PLA typically prints with a bed temperature of 60C, so it’s going to heat the enclosure less than ABS right off the bat. Always make sure to print with an enclosure fan and monitor the internal temperature, which ideally should be in the 30-35C range or lower if you can get it.
If you’d like to lower the temperature further you can always buy a more powerful fan, but the easiest thing to do is just crack the front door a little to increase airflow. But won’t that let out all of the volatile organic compounds coming off the hot end? The key is the negative pressure combined with the fact that the particles are extremely small and light. As you can see, the fan keeps the air flowing in and the harmful particles flowing into the vent or filter.

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3D Printer Design Matters
The other part of the equation is the printer design. Those printers where the hot end is at the top of the enclosure make it easier to achieve higher temperatures because the hot air rises to the top, and the vertical hot end position is fixed. Those printers with the hot ends at the bottom are always going to have more problems managing temperature simply because the temperature is more likely to vary as the hot end goes from the bottom to the top of the enclosure.

Let Us Help

If you’re looking to achieve a particular temperature with your enclosure, let us know and we’ll give some advice on how to manage, but it’s really not that hard:

Lower Temperature = More Cold Air
Higher Temperature = Less Cold Air

Pro Tip: measure your current temperatures before attempting to make any changes. We get support calls saying “my enclosure is too hot” or “too cold” but they didn’t actually measure the temperature. Without measurements, it’s impossible to say if a printing problem is temperature related or not.

Tips and Tricks
On some surfaces the enclosure can slide around a bit. In those cases try using thin double sided tape on the corners to hold it in place. Another issue is the magnets in the door are strong. You can either use two hands to open the door, one holding the enclosure and another to open the door, or reduce the affects of the magnet by adding a piece of black electrical tape to the side of the strike plate that contacts the magnet. You’ll need to adjust the location of the magnetic latch by loosening the wood screws, moving the latch, and retightening.

DIY Tool Holder
Our favorite customization is to add magnetic tool holders to the side. One end can be attached via the same hole as the corner connectors, but the other end will require drilling a single hole. You can find magnetic strips like this all over Amazon or your local hardware store.

MK2/S Height Adjustment
The enclosure height is designed to fit the MK3/S be default. If you happen to own an older model MK2/S then you will notice the power supply duct opening is at the wrong height. This is because the MK2 didn’t come with feet. Luckily, with a little extra effort you can make it line up just right.
Start with the 30mm Prusa foot variation on Thingiverse. Using your favorite STL editor you can add 2mm to the right. Then purchase these bumpers to place on the bottom of the feet, and your Prusa will be quieter than ever AND match the vent hole on the enclosure.