jitsbuild-platform [Bukobot 3D Printer Instructions & Docs]

======jit's build:  Platform======

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Shown here is the 8" heated platform.  The other types of platform assemble in a similar way.

If you don't have the heated platform, skip down to [[jitsbuild-platform#mounting the platform|here]].

=====Heated Platform=====

Find this ([[bukobot-parts-list#platform|bag 6a]]):

{{wiki:jitsbuild:platform-heater-kit.png}}

Get out your heated platform.  Leave the glass sheet in its protective packaging.

If the lugs aren't already crimped onto one end of the thick red & black zip cord, get out your crimping tool and crimp them on.

Put the screws on the top of the bed and the nuts on the bottom (the top says "HOT SURFACE!" around the edge), as shown below, then attach the spade lugs:

{{wiki:jitsbuild:heater-connections.png}}

Red goes to positive, black to negative. Cover the screw heads and the nearby conductive areas with kapton/polymide tape to avoid any accidental short circuiting.

The flat side of the lugs goes against the heated bed. Once the connections have been made, it's best to zip tie all four wires to the heater platform as shown.

{{:heater-strain-relief.jpg?800|}}

(In some of the images below, the lugs are shown attached to the top of the platform.  It is recommended that they be attached to the underside instead, as shown above.)

While you're here, look inside the little hole in the middle of the heated bed:

{{wiki:jitsbuild:platform-thermistor.png}}

The tiny thermistor should be touching the side of the hole, or really close to it.  If necessary, move it closer to the wall of the hole.  It must not protrude from the hole. Don't break it. The pre-installed thermistor from Deezmaker is very sensitive, so as long as there is kapton tape (polyimide - the gold tape) covering the bottom and the thermistor is close to the inner wall of the hole, it should be pretty accurate.

For best results with some plastics, the heated bed should have a layer of thermal insulation under it. The kit comes with a length of White Thermal Ceramic Insulation Cloth. 

Cut this into four equal lengths, about as long as shown below (you may have some left over, which you might find useful on your hot end). Don't cut it so long that it covers the screw holes.  Before peeling off the white plastic that covers the adhesive, lay out the insulation to check how you will apply it (see the below image for an example).

The ends of this woven material tend to unravel, so it's recommended that the cut ends be covered with polyimide tape (not shown here) before adding the insulation to the platform.

Remove the backing on one strip at a time and apply it to the bottom of the heated bed as shown. The bottom says "HELIOS", and the top is the side where "HOT SURFACE!" is printed around the edge. 

{{:headed-platform-insulation.jpg?800}}

You might want to add some polyimide tape around the edges to hold things in place.

Some people find that the insulation can fall off. To prevent this, you can outline the cloth with polymide (Kapton) tape, half on the cloth and half on board and in between each strip to help the edges from peeling with time.

{{ :img_2389_-_version_2.jpg?800 |}}

Detailed documentation of the heated bed insulation on one build can be found [[heated-bed-preparation|here]].  If you come up with something better, please document it there.

=====Mounting the Platform=====

If you don't have your platform out, get it out.  If you have a glass sheet, leave it in its protective packaging for now.

Find the remaining parts from the platform mount kit ([[bukobot-parts-list#y-carriage|bag 14b]]):

{{wiki:jitsbuild:platform-mount-kit2.png}}

Put nuts into the hexagonal depressions on the two adjuster wheels in the usual way.

Put the two long flat-head screws through the holes in the corners of the front edge of the platform (the back edge of the heated platform has the hookup wires).  Their heads go into the chamfered holes in the top surface of the platform.  Nuts go on the other side:

{{wiki:jitsbuild:platform_underside.png}}

Move the Y carriage to the front, and position the platform on top of it.  If you have the heated platform, the wires lead out toward the back.

The center hole at the back end of the platform goes over the standoff at one end of the Y carriage.

Put one spring under each of the long screws:

{{wiki:jitsbuild:platform-springs.png}}

Put the short flat-head screw through the hole above the standoff, and screw it down just until you feel just a little resistance.  Do not tighten this screw any further.

Push the long screws down through their holes in the metal plate, and screw adjuster wheels onto them on the underside of the platform, with their nuts facing down (the nuts may pop out when you do this, don't lose them):

{{wiki:jitsbuild:platform-adjusters.png}}

Before you apply the glass plate, clean the top surface of the heated bed with isopropyl alcohol.  Let dry completely.

=====Glass Platform Plate=====

The glass platform plate is installed on top of the main platform, and is the surface where the extruder deposits the material as it creates the part. Because this surface determines the bottom of your part, it's essential that it is very flat. Depending on the material you are using (e.g. PLA vs. ABS), you can treat the glass with different kinds of tape. 

  * PLA: The typical surface used for PLA is blue painter's tape. When using the blue tape, the platform does not need to be heated. For a smoother bottom of your part, you can use the Kapton brand polymide yellowish tape. When using the polymide tape, set the platform to be heated to 60 degrees centigrade.
  * ABS: Use the polymide tape surface for creating ABS parts. Heat the platform to 110c - 120c (start with 110c, and if the material doesn't stick well, try upping the temperature).

If you don't have a heated platform, start at step 3 since you don't need to apply the polymide tape. If you have the heated platform, you can set up the glass for greatest flexibility using both polymide tape and blue tape. This approach is documented below.

  - Clean the glass with glass cleaner to remove any residue
  - Apply the polymide tape in parallel strips, making sure it is as smooth as possible, and no overlap of the tape. The goal is to make the surface as flat as possible. The tape is very sticky, so a good approach is to angle the tape with just the matching edge lower to align it with the previous strip of tape. Then lay the tape down smoothly and press to seal it to the glass
    - Don't stretch the tape as you apply it, or it won't go down smoothly.
    - Avoid creating any bubbles - this can be hard and you can see there are a few in the example photos
    - Wrap the tape ends under the bottom of the glass, but make sure there is only one thickness anywhere on the bottom to maintain the levelness of the glass
  - Apply 2" blue painter's tape perpendicular to the polymide tape so that when you remove it (to replace/refresh), you don't peel off the polymide tape as well. Leave the ends of the tape loose.
  - Set the glass on your main platform, aligning it over the markings so it is centered. Be sure the glass isn't blocking any screws or sitting on the electrical connections in the back.
  - Smooth down the ends of the blue tape on the platform
  - Use small clips to hold the glass in place. If you put the clips over the glass, there's a danger of the extruder head hitting a clip. An alternative that's safer is to put the clips only on the base platform as stops on all four sides. This combined with the tape ends should hold the platform in place.

{{:glass-polyimide-tape.jpg?800|}}

Apply the polymide tape as shown, with no overlaps.

{{:glass-applying-blue-tape.jpg?800|}}

Then apply the blue tape perpendicular to the polymide strips.

{{:glass-finished.jpg?800|}}

Mount the glass on the platform.

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//The contents of this page may be re-used under any of the following licenses:  The [[http://creativecommons.org/licenses/by-sa/3.0/|Creative Commons Attribution-ShareAlike 3.0 Unported License (CC BY-SA 3.0)]], or the [[http://www.gnu.org/copyleft/fdl.html|GNU Free Documentation License (GFDL, version 1.2 or later)]].  Nothing on any of these pages is there to tell you what to do, only what other people have already done.//
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