WIP Updated PrintrBot Assembly BD approved

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WIP Updated PrintrBot Assembly BD approved

Postby CL1 » 2012-Apr-Sun-02-Apr

WIP= Work In Progress

Consider this a placeholder. I just typed an update improvement of what's posted below for 2-1/2 hours which was lost when I was asked to login (while being shown as already being logged in) to preview. I've asked the Board admin (Plexus) if my work can be found in system logs or some such, and I'll await his reply with prayers and hope that the very much improved version is somehow still available! I am heartbroken right now.

Did some research on PHPBB and it Seems I've found an answer. http://www.phpbb.com/community/viewtopic.php?f=46&t=2119996
Not what I was hoping for, but at least it's a known fault for PHPBB. I've asked the Board admin plexus to put this info somewhere prominent so that contributing members will see it. It really hurts to lose your work when you're not expecting to.

Sorry you guys didn't get the complete updated Assembly doc yet, I'll get on this again ASAP.

CL1

Meanwhile here is the original post from the other thread which has at least the basic ideas.
You can see the threaded rods in the base stick out about 1/2" on each side. They could be a little shorter.


The newer PB's base rods will extend quite a bit farther than that! Note to builders, put the extra rod length to the right, with the leftmost nuts flush with the end of the four base threaded rods. There *may* be an upcoming reason to do so ;)

Also, while too late for you, a different assembly order than what was shown in the Videos has proven to be useful in dealing with the variable width of the Base pieces that you ran into. Not everyone has assembled as many of these as Brook and so won't have the experience to just eyeball it!

If you begin assembly with the CARRiage and X Axis instead of the Base, then the distance between the vertical Z rods will be correct for your particular set of parts and rods. You then match this distance with the 4 threaded rods of the base to complete the basic assembly. A side benefit is the parallelism of the Z AND Y rods is easily attained without any special measurement.

Step by step:
Put two or three linear bearings in the CARRiage plastic piece and then assemble it onto two smooth rods. Two bearings work fine and will maximise the PrintrBot's build volume. Using three linear bearings uses up a bit of X travel but will increase overall carriage rigidity. If you DO use three, double up at the top of the carriage, with the single bearing below. An extra bearing is included with the kit to allow for this choice. A single screw and nut between the bearings will hold the 2 or 3 linear bearings in place. Don't forget to attach the EXtruder MounT plastic piece at this time too! It also uses a second screw and nut, and both nuts are in nut traps in the EXtruder MounT itself.

Note: Another good idea is to put the bearings onto the smooth rods FIRST whenever possible. Otherwise you may accidentally get a linear bearing off axis of the rod and loose a few of the tiny ball bearings from the linear bearing as you push the smooth rod through. This is more likely when you are pushing a rod through TWO already installed Linear bearings. This is a second reason for the *extra* linear bearing included. Always *twist* the smooth rod as you *slowly* and *carefully* push it through a linear bearing. Be careful!

Now the two smooth X axis rods with the CARRiage in place go into the XMOTor and XIDLer to continue the X axis assembly. Push the two parts towards each other until you feel the rods bottom out in the XMOTor and XIDLer. You can add the X motor, Idler bearing with large washers, X Endstop switch and X belt now or later to complete the X axis assembly. Personally, I think it's easier to do now when you can easily move the involved parts all around with ease.
Next put the four Z linear bearings into the XMotor and XIdler plastic blocks. Push two smooth rods into the Base pieces, and then put those CAREFULLY into the Linear bearings of the X axis. As noted above, it may be wise to put the smooth rod through the XMOTor XIDLer first. Then add a linear bearing to each end and push them into the Plastic part while they are already on the smooth rod.

Use Wire-tyes to fasten two Linear bearings to each base piece. See Brook's first video for details. Again, consider putting the smooth rod through the linear bearings BEFORE attaching them to the BASE parts. Putting the YBAR ends (3) and YLIMit plastic P-shaped pieces on the ends of these rods will help keep them from falling out of the linear bearings as you continue assembly.

Then add the BASE pieces to the lower ends of the Z rods which are sticking out of the X axis assembly.
Now you can stand the whole assembly up on the base pieces and you will see that the distance between the BASE parts is automatically correctly set! If needed, rotate the BASE pieces so the linear bearing which support the table are BETWEEN the two Upright Z Rods.

Now add the four 5/16 threaded rods and 16 nuts. Think for a minute about how to put the nuts on so you don't find one or more missing halfway through the step! I'll mention again that you may want to place the left end of the base rods flush and let any overhang of the threaded rods extend to the right. Refer to Brook's first video to see how the left side is tightened up first so that adjustments are made on the right.

Note: If you temporarily attach the table you will more easily get the Y axis rods into parallel alignment at the same time as you are adjusting the Z rods for vertical, parallel and square. Simply rasie and lower the Z axis bridge assembly, and you'll need no measuring tools to get the 4 threaded base rods correctly set for width and vertical. Slide the temporarily attached table toward and away and you'll see that it will help you to easily get these same four threaded rods set for best table travel and alignment too! Take your time, and with a few minutes of adjustment, you'll have a machine that is self-aligned to be square on all three axes! Tighten all 8 of the nuts on the right to preserve this alignment. (The left eight were already tightened flush)

That covers important points of the New-style basic machine assembly. Brook has approved this method of assembly.

Next steps are to remove the table to add the Y and Z motors. Use the two wooden C-shaped pieces to wire-tye the PrinterBoard PCB to the upper base threaded rods with the connectors pointing down and the USB and SD slots to the rear. It's a tight fit, but it will all make sense with the parts in front of you.

CL1

Here below is another partial version of the original PB build I just wrote. Moving it here to be more central and topically located. It and the above will be integrated into a single cohesive doc ASAP. But for now, it's better than nothing and is at least up to date and accurate for new part names.

Amoril wrote:Thanks for the quick replies. CL1 I show 177mm exposed on the X-axis rods. I've pushed them in as far as they go for sure =). I've looked at other people's builds (such as the post by PaulRAC) and my bed does look different, the screw holes themselves are in different locations, I'm thinking that's the real reason I'm off?

Thanks for the tip on the end-stops, no video or instructions I've seen include where to put them so it's something of a mystery to me (I'm mechanically challenged apparently, lol). CL1, you mentioned you have updated build instructions, where would these be, I probably missed them in one of your posts.

Thanks!


Hi again Amoril,

Since it measures 178mm, you're fine. On second look, I think you may have an LC bed (If not an older non-production development bed by mistake.) The LC Bed is differentiated by its straight sides, where the original PB bed with its indents was a very important look that Brook wanted to keep.

Here's what to do from where you're at, step-by-step.
Remove the bed. Loosen all four outermost Right side nuts on the base threaded rods. Loosen the LEFTmost top rear nut on the upper rear Base threaded rod. Spin the related inside nut to allow for about a 3mm thickness to be added. Find the ZEST printed part, which is a long rectangle with a 5/16 hole at one end and two switch holes at the other end. The thickness is created by three walls. Put this part on the upper rear threaded rod LEFT of the left base so that its thicker portion overlaps the TOP of the LEFT BASE. RE-install the 5/16 nut to hold it in place vertically. This is the mount for your Z EndSTop switch.

Next, build up the carriage using 2 or 3 bearings. If you use 3 put the doubled bearings on top. There is an *extra* linear bearing for this purpose, or to replace one which is ruined by pushing the small balls out accidentally with a misaligned Rod. There are two screw holes in the XCAR and also the Extruder mount. Put two hex nuts in the nut traps of the Extruder Mount. Join the Extruder mount and the XCARwith the middle screw between the bearings. Find the plastic part which looks like a short piece of right angle iron, with a 3mm hole and a slightly smaller hole. This is the XESF (X EndStop Fix) intermediate part to adapt your XCAR to hold a 6-32 actuating screw. Fasten this to the XCAR/ EXMT assembly using the upper screw hole. See my post on Endstops in the Assembly section of this site for added details.

Now slide the XIDler and XMOTor off the rods, and CAREFULLY twist the rods into the two or three bearings of the carriage. AFTER the rods are in the linear bearings of the carriage, re-install their ends into the XMOtor and XIDLer and fully seat. At this point I usually finish up the rest of the Bridge adding the X stepper motor and the idler bearing and belt, etc.

Now comes the important bits. Put one loose linear bearing on each vertical rod. Each will naturally fall down to the BASE by gravity. NEXT, put the partially or fully assembled Bridge over the Vertical rods WITHOUT any linear bearings installed. Add a single bearing onto the vertical rods above the TOP of the XMOTor and XIDLer blocks. These bearings will also naturally fall own to the top of the blocks. Now insert these TOP bearings into the XMOTor and XIDLer blcok and press them in until they are FLUSH WITH THE TOP of the XMOT and XIDL bodies. This step assures you of maximum Z axis travel and build area. Then line up and insert the remaining bearings, first one side then the other from BELOW the XMOT and XIDL. Press them in as far as they'll go. They will NOT be flush, but will stick out some from the bottom of the Bridge assembly.

Your Bridge will now move easily up and down, but the base will be wobbly since you released the outer right base nuts from the threaded rods in the 2nd step above. Can you see how the Bridge will now self jig the Vertical rod distance to match its width and by moving it up and down you can gauge and adjust parallel too? At this point I would say to temporarily attach the table, but it appears your table is not correct. You can check the distance between the mounting holes. left to right they should be 160mm. You can use this number if you want to drill new holes.

Anyways, with the table temporarily fastened, and the Bridge riding freely up and down on the Z axis rods, the Bot self-jigs for you to accurately set the position of the inner four and outer 4 nuts on the right ends of the four threaded base rods to achieve flat square and perpendicularity between axes. Once you have these adjustments made and the eight nuts tightened, you remove the table to add the rest of the base parts; i.e., Y stepper, Z steppers, PrintrBoard PCB, and also the YESF (Y EndStop Fix switch mount) which is the third small plastic part you may not have been sure about. It is held to the LEFT BASE piece facing the FRONT by an M3 screw through the right front motor hole of the LEFT BASE printed part. Now move that YEST from the Rear right rod to the left front and you'll have a place to put an actuating screw for the switch you'll mount to the YESF with a wire-tye.

Then you add the Z motors , the Ymotor and Guide, the Y belt and clips, and so on.

Hopefully this will get you back in business! (And I needed to re-write some of this since I lost it last night, so I thank you for the opportunity to do so!)

CL1
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CL1
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WIP Updated PrintrBot Assembly BD approved

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