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Bill A's A8 Printer Build

Bill Arnold

Bill Arnold

1974
Staff member
Messages
8,631
Location
Thomasville, GA
OK, so I received my package last Thursday evening via FedEx. It appeared to be in good shape, so I cut the tape, opened the box and removed the three styrofoam trays holding the parts. Everything looked well-protected and in great shape.

The acrylic parts are protected with a paper/plastic material that I found fairly easy to remove, although it was tedious as heck! I did that process Thursday evening.

A8_Step00.jpg


Day One of actual build (Friday):
The first step was screwing the uprights and their supports together. Exciting, huh?

A8_Step01.jpg

At the end of the day on Friday, I had gone through step 9 of 27 and is was 5:00 - somewhere.

A8_Step09.jpg


Day Two (Saturday):
Steps 10 through 18 were done in the morning. That got me to the point of having the bed support and Y belt installed, as well as the Z motors with associated lead screws and guide rods.

A8_Step18.jpg

I continued in the afternoon, getting the extruder and its fans installed, along with the X motor and belt. I also started getting the wiring routed through the system.

A8_Step22.jpg


Monday

Not a lot to report today. I got the H-frame flipped as per Darren's link. LOML said I needed to take her to lunch and I know who the real boss is! I wanted to look at storage containers and get something for the 3D printer filament, so we had lunch at the Chinese buffet next door to Walmart, then toured WallyWorld. By the time we got back home, I was ready for a nap; stayed up too late watching football Sunday night, I guess!


Tuesday

Mounted the system board to the printer and routed cables to it. Got some of the cables contained in cable wrap. Made sure of all connections and turned the system on. Everything appeared good, so I did a homing run. That's when I discovered an issue with the Z-axis endstop switch; it would have allowed the extruder nozzle to hit the table if it weren't already aligned off the lower left. So, I adjusted the switch mount higher to take care of that problem. Next, I researched the Z-axis issue and found lots of solutions to allow for fine adjustments to Z.

Another issue I had was mounting the 12VDC power supply. Unless I'm missing something, there aren't any holes in the right locations to match the two slots on the power supply case. Easy enough to solve with a drill.

A8_Step27.jpg

That's enough for today. I ended up playing plumber like Jim Delaney, although nowhere near as serious as his problems!

Just as I was closing down for the day, Bobbie came down the driveway with the mail delivery. I now have the MOSFET to offload the heat bed from the system board along with the capacitive leveling sensor. More fun tomorrow!


Wednesday

Today was mostly a bust as far as progress on the printer is concerned. I had an appointment with my cardiologist at 9:45am; had to be there at 9:30. Finally got taken to an exam room at 10:05; 10:45 the doctor still wasn't in there, so I opened the door to let them know I had another life. Finally, about five minutes later the doctor came in. They had a couple of emergencies, etc., etc., etc. Anyway, I finally got back home about 11:30 - in time for lunch!

Then, LOML reminded me we (we?) needed to get the bat house up, so I ran to Lowe's for some sticks of PVC pipe. Got everything all set up and she helped me swing the thing up in the air.


Thursday

I started the day getting the MOSFET heat bed switch installed. Then I started testing some functions. When I turned on the heat bed, I heard the fan slow down so I started checking the power supply voltage. I knew it had been about 12.1VDC with no load and the adjustment worked.

On further review...turned out to be a headspace problem. I thought I had switched the power supply to 110VAC, but had not done so. All is well in electron land now, so we'll see what the afternoon brings!


Friday

Today, I did a lot of reading to try to understand all the steps necessary to get a file printed.

I spent quite a while getting the bed leveled, then was ready for the next steps. When I loaded filament into my printer for the first time, it appeared to bottom out but I didn't get anything from the nozzle. So, I disassembled the extruder to see what was going on. There was a slight misalignment between the stepper and the opening to the nozzle, so I loosened the bolts and wiggled the parts around a little. Got that going just fine with a good stream of PLA from the nozzle. I chose a gcode file that was on the SD card and started it after doing a Home All. The nozzle was about 0.2mm above the bed at the 0,0 location. As the print started, it moved about 3mm above the table, went to the starting point and stayed above the table, not returning to the Z0 location or 0.2mm. The resultant print is shown in the photo. I stopped the print after a few seconds.

A8_StPrt00.jpg

I need to go through CURA and see how it operates and create my own gcode file based on my machine to see if that fixes the print.

Any thoughts?


I'll keep adding updates to this post rather than in replies.
 
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Darren, thanks for the updates. I thought the h-frame looked a bit strange, but it worked so I left it as is. I'll change it first thing tomorrow. I have the four shims in place - have to flip them to the other side now.

OK on the Z rod - I'll check it. That's like an issue on the SO2 CNC.

I've already been looking at the "rest of the story" page.

At this point, I'll be satisfied if I can get a test print done by the end of the week! ;)
 
For the z axis screws, they have the couplings way to close to the motors, you also don't want the screw and motor shaft touching inside the coupler, which will then allow the coupler to do its job and flex a little. This will give you enough play to get the screw rod up through it's hole to support that end, which will help give a smoother print as they get taller as they won't be wobbling as much. There are a couple of other solutions for supporting them too, but this is the basic way.

2016-12-27 22.59.23.jpg2016-12-27 22.59.27.jpg

sorry, just realized that the second on is reflecting the guitar I have on the wall above it, but it's the top plate, showing the screw rod sticking up in the hole. ;)
 
I was going to ask about the Z axis lead screws because mine don't extend through the holes in the top bracket. Adjusting the coupler will get that fixed. I think I have a Z axis bearing left over from my SO2 that might also help at the top of the lead screw.
 
There are different schools of thoughts on the z axis lead screws. Some say let them flop around as the linear bearings on the rods are straighter and constraining the z axis screws can cause binding.

I had one of the lead screw bearings that was misaligned on mine. Had to take it out and put it back in straight. It was off so much it was causing the motor to skip steps.

I haven't moved mine up through the holes yet. In fact, mine don't really look like they line up to go through the holes, so I've let the flop around.
 
Thanks, Brent. I'll keep an eye on the alignment as I work through the steps. My left lead screw appears perfectly aligned with the top hole; the right one is offset slightly.
 
Bill Arnold said:
:huh:
Click to expand...

Issues? for the offset, I'd mostly check to see if the motor is the same distance from the center of your rail as your rail is to the distance to that hole on top. I want to say it was about 22mm center to center. If not the nut or motor may need to move over. My left one is a bit close on one side of the hole, but it never binds, so I haven't bothered fixing it.


Edit: Just noticed the comment on the power supply. Mine is about 2" off the desk, only three screws hold it on, so try the holes a little further up, hopefully they didn't change the ps design.
 
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See my OP for explanation of the power supply regulation problem. Or, non-problem! I need a nap!!

As to getting it mounted, I used one existing hole on the upright and drilled another to match the PS module.
 
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Bill Arnold said:
Today, I did a lot of reading to try to understand all the steps necessary to get a file printed.

I spent quite a while getting the bed leveled, then was ready for the next steps. When I loaded filament into my printer for the first time, it appeared to bottom out but I didn't get anything from the nozzle. So, I disassembled the extruder to see what was going on. There was a slight misalignment between the stepper and the opening to the nozzle, so I loosened the bolts and wiggled the parts around a little. Got that going just fine with a good stream of PLA from the nozzle. I chose a gcode file that was on the SD card and started it after doing a Home All. The nozzle was about 0.2mm above the bed at the 0,0 location. As the print started, it moved about 3mm above the table, went to the starting point and stayed above the table, not returning to the Z0 location or 0.2mm. The resultant print is shown in the photo. I stopped the print after a few seconds.

View attachment 98283

I need to go through CURA and see how it operates and create my own gcode file based on my machine to see if that fixes the print.

Any thoughts?


I'll keep adding updates to this post rather than in replies.
Click to expand...

Post the gcode. It sounds like it didn't tell it to do a z movement. There are a few test prints out there for checking your bed's levelness you might try once it's at least getting down the right height on the first layer.

http://www.thingiverse.com/thing:13053
 
I was confused when you mentioned the OP. In general, it's a lot easier to follow a thread if you add a new post when you make progress, as opposed to editing the first post in the thread. Kind of breaks the whole time/space continuum....


That's a pretty classic, not getting the nozzle to the table issue.

1) I'm assuming you are using the mechanical Z stop switch. Adjust that until when you do a G28 that it gets close to the bed.
2) Then level the bed so that a strip of printer paper fits under the nozzle, but that it has tension on it.

If you are manually leveling the bed, you want to make sure you have that sucker right down on the table, most likely right around .2mm or below.
 
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Brent Dowell said:
I was confused when you mentioned the OP. In general, it's a lot easier to follow a thread if you add a new post when you make progress, as opposed to editing the first post in the thread. Kind of breaks the whole time/space continuum....

That's a pretty classic, not getting the nozzle to the table issue.

1) I'm assuming you are using the mechanical Z stop switch. Adjust that until when you do a G28 that it gets close to the bed.
2) Then level the bed so that a strip of printer paper fits under the nozzle, but that it has tension on it.

If you are manually leveling the bed, you want to make sure you have that sucker right down on the table, most likely right around .2mm or below.
Click to expand...

For now, I'm using the mechanical stop switch. When I can print successfully, I'll create a holder for the sensor.

To level the bed manually, I used a small piece of clear polycarbonate that is 3.2mm thick. My thinking is that it will compensate for my glass that is 3mm thick plus add the 0.2mm the nozzle should be above the bed. That part works as far as getting the Z axis to zero when it's 0.2mm above the glass. But, when I start a print with one of the files on the SD card, Z is lifted above the glass to move, then never goes back to its zero point. Last night, I created a gcode file with CURA, using the correct values for the A8. I need to compare it with the start of the file from the SD card.
 
I'm looking at gcode for a box on the SD card that came with my printer. I have my printer Z axis set to zero at about 0.2mm above the glass on my table. There is a move command to raise Z to 15.0mm. When printing starts, Z never lowers to the 0.2mm level. There are G92 commands for relative positioning. Shouldn't there be a G90 to return to absolute positioning? The printer display shows Z0.20 when printing starts but the nozzle is more like 3mm above the glass. What am I missing?

M140 S50.000000
M109 T0 S200.000000
T0
M190 S50.000000
;Sliced at: Thu 07-07-2016 18:12:19
;Basic settings: Layer height: 0.2 Walls: 1.2 Fill: 15
;Print time: #P_TIME#
;Filament used: #F_AMNT#m #F_WGHT#g
;Filament cost: #F_COST#
;M190 S50 ;Uncomment to add your own bed temperature line
;M109 S200 ;Uncomment to add your own temperature line
G21 ;metric values
G90 ;absolute positioning
M107 ;start with the fan off
G28 X0 Y0 ;move X/Y to min endstops
G28 Z0 ;move Z to min endstops
G1 Z15.0 F3000 ;move the platform down 15mm
G92 E0 ;zero the extruded length
G1 F200 E3 ;extrude 3mm of feed stock
G92 E0 ;zero the extruded length again
G1 F3000
;Put printing message on LCD screen
M117 Printing...

;Layer count: 60
;LAYER:0
M107
G0 F3000 X60.80 Y76.30 Z0.20
;TYPE:SKIRT
 
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