MakerFarm 12" Prusa I3V - my build, usage, and mods

Quote
itchytweed
Note to forum: I am not a bot. Your algorithms are stereotypical fail.

Are you sure of that?
If you were a bot how would you know how it feels to be human?

Quote
djmartins

Quote
itchytweed
Note to forum: I am not a bot. Your algorithms are stereotypical fail.

Are you sure of that?
If you were a bot how would you know how it feels to be human?

Love it!!!

New thermistors are on the way. They are made by U.S. Sensors and not Epcos. I have even made a module for Marlin's thermistortables.h for it from the curve spreadsheet that U.S. Sensors puts out for it. These glass thermistors are rated from -40c to +300c. We shall see.

This is a picture of the new thermistor that will be going into the hotend. Talk about small....


BTW, this little beauty is Kapton taped to the outside (just floats in the hole of the Hexagon) and the silicone cover is over it. This also curves out to Thermistor #1 in marlin's thermistortables.h. No need for a separate table for this small piece of cuteness.

Edited 1 time(s). Last edit at 06/25/2015 11:15PM by itchytweed.

This is from [www.rtpcompany.com]:

MOLDING AND PROCESSING GUIDELINES FOR PLA (POLYLACTIC ACID) COMPOUNDS

In order to achieve optimum performance from articles injection molded out of RTP Company’s polylactic acid (PLA) based compounds, it is important to understand the proper injection molding conditions for these materials. PLA is a semi-crystalline polyester thermoplastic. Because polyesters are prone to hydrolysis, molders must pay particular attention to ensure material is dried prior to molding. Similar to other semi-crystalline polyesters, PLA can be molded into either the amorphous or crystalline morphology by changing molding conditions.
Drying

PLA is a hygroscopic thermoplastic that readily absorbs water from the atmosphere. The presence of even small amounts of moisture will hydrolyze PLA in the melt phase, reducing molecular weight and causing loss of properties. Prior to injection molding, we recommend that all PLA containing compounds be dried to a moisture content below 0.02% (200 ppm) using a desiccant dryer with the capability of delivering air with a dew point of -40°F (-40°C).
Most PLA compounds that RTP Company will be supplying will have amorphous pellets. These pellets can become sticky/tacky on the surface when heated above their glass transition temperature (Tg) of 130°F (55°C). It is important that drying temperatures do not exceed 130°F (55°C) or pellets will stick together and will not flow out of the dryer. Alloys with other polymers, ie PLA/PC hybrids, can be dried at higher temperatures.

Been running Slic3r 1.2.9. Ran my calibration cube (EVERYONE has a calibration cube) using my regular settings. Then I turned on the pressure regulation function. Big difference can be seen - win for P. C. Also, there is a difference in the feel of the sides. The P.C. printed block is noticably smoother between the layers. I do though have my max speed at 50 mm/s just to limit pressure in the hotend.

About moisture: PET and PETG filaments don't absorb moisture (they are used for water bottles). Also, PET does not warp, or smell. Seems like a good plastic for non-enclosed printers.

Quote
RRuser
About moisture: PET and PETG filaments don't absorb moisture (they are used for water bottles). Also, PET does not warp, or smell. Seems like a good plastic for non-enclosed printers.

PET and PETG do not absorb water. But if any moisture enters the extrusion process, PET will fail miserably. I have been in plants where they run industrial dehumidfiers to dry out the PET and keep it in a sealed system so humidity can't get in and affect the parison molding process.

I look at it this way, no moisture, me happy. Silica gel and a sealed tub have become best buds together.

I was doing a relatively tall print. It completed but it was fail. Come to find out that the steppers lost counts even though I have the CL set for 1 amp. Found out that the steppers on the unit are 4 volt / 1.5 amps. So, it looks like the X and Y axes get turned up a tad. Z is two motors with their own drivers so there is no issue there.

Followup: Increased pot voltage to 0.75 volts for X, Y, and E drivers. Doing a delicate print job now and the stepper are barely warm to my touch. IR temp on the lams says 40 deg C. That is way fine. Now to see how they do on a long print job.

Edited 1 time(s). Last edit at 07/08/2015 07:47PM by itchytweed.

Been running a print job overnight at 40mm/sec velocity and at 1.5 amps CL on the high-power DRV88's. Ambient room temp is at 20 deg C. Steppers were coming in at 65 deg C. I have not seen any apparent print shift yet. Also, I printed out a couple of beveled idler pulleys out of PETG to go over the X and Y axis belt bearings. This should keep the belt from rubbing against the walls and it has resulted in less friction to the movement.

Bought some angle aluminum. The bowing of the wood cross pieces for the Y axis has become too much. The angle will act as a stiffener for the cross piece and and anchor point for C-clamps to keep it from walking off the table.

Pictures to follow.

Is that the piece at the very front of the bed?

As promised, before and after pictures.

This is the front cross piece supporting the Y-axis rails and turnaround idler:

Notice the gap representing the bow.

Here is the angle support installed:


I also have one that I did for the other end as well that I do not have pictured.

This post has nothing to do with the printer, which at this moment is printing out a set of replacement gears for the extruder out of PETG.

PLA is notorious for sucking up humidity and crapping prints. There are some products being sold on the market or can be made that help with this issue. My solution was easy. I have a 20 gallon tub with a lid. I put foam tape along the top part of the tub to help with the seal to the lid. Inside, I keep the filament rolls. The secret sauce here is about 2 lbs of Silica Gel granules bought from a local hobby store. These are the same that are used for drying out flowers for art arrangements. The gel granules are in their own tub inside of the big tub. I have the humidity inside of the tub down to 16%. Can't argue about that.

When it comes time to change out the granules, I have a second batch of granules that are dried out and they go in. The original batch gets the oven drying treatment.

Simple and easy.

Been some time since visiting this posting so here are some updates.

The PETG gears are working wonderfully. Plus, I have fallen in wuv with the MicroCenter/ESun PET-G filament. It is so easy to print with - once you get it to stick. It's that first layer....a little glue stick, heat plate to 65 deg C, get a good squeeze going on that first layer - done. It's all about that first layer....first layer....

I am through using glass bead thermistors. The glass ends up cracking off and failing the print. Switching to K-type thermocouple on Hexagon. Not pleased about having to do it but replacement is proving to be annoying. Omega.com has bolt-on thermocouples with fiberglass insulation rated to 450 deg C for a good price and Makergeeks.com sells an adapter board to do the conversion deed.

Hi,

As I see the bended front plate on your Y axis chassis,
I wonder if Makerfarm's plywood quality is cheap
or if the belts are overtight ?

++JM

Quote
J-Max
Hi,

As I see the bended front plate on your Y axis chassis,
I wonder if Makerfarm's plywood quality is cheap
or if the belts are overtight ?

++JM

Answer: Belts are tight. The 12x12 base haas a lot of inertia and it takes a bit to move the energy from the stepper to the platen and not have any bouncing at stop. I have managed to make this machine more than what it was when I bought it and I have to credit MakerFarm for building such a base to grow on.

Wood, under tension will bend. The angle aluminum has far more resistance to the bending so it can withstand the strain. Without the flex, there is better control in the Y axis. Also, as an added benefit, it makes a great attachment point to clamp the printer to the desk with a c-clamp so it does not take any unwanted excursions around the tabletop or a visit to the floor.

Eventually, I plan to eliminate the belts and go to leadscrews on the X and Y axis and both using ABN's.

Hi,

Thx for your awnser. I did not know it was the 12" model.
Makerfarm should have upscale the frame too.

Leadscrews can't have a quick acceleration.
Maybe it will increase printing time.
Digital servo instead of stepper motors can run
a very fast printer even with leadscrews.
If your rich enough to afford it

++JM

Edited 1 time(s). Last edit at 09/17/2015 09:28AM by J-Max.

"I am through using glass bead thermistors. The glass ends up cracking off and failing the print."

What is causing them to crack?

Quote
RRuser
"I am through using glass bead thermistors. The glass ends up cracking off and failing the print."

What is causing them to crack?

Thermal cycling and the resultant shock. I don't think that the glass is pyrex and certainly not corning. Plus, the layer is so thin as to keep temp delay to least possible. I have several spares and I am using one but I have wrapped it in one layer of Kapton tape to keep it out of direct contact but it stays in the hole centered. There is a difference in temp leveling response but the amount is insignificant. When I get the thermocouples, the bead comes out.

Nutz!!!

It appears that the 16U2 locked up again.

Quote
itchytweed
Nutz!!!

It appears that the 16U2 locked up again.

Both the RX/TX lights were shining at me. Reloaded the 16U2 firmware and we be back in business.

Adafruit comes through again.

K type thermocouple - 1 meter length. AD8495 breakout board. Running off of 5 volts and the output is coming in on A10.

Wrote a new table for the critter and recompiled Marlin. Just did a print and it sure looks good.

The thermocouple is anchored to the Hexagon head by an M3 screw with a washer. The thermistor hole is just right for a M3 tap to thread. A short M3 screw with a washer puts the squeeze on the thermocouple. Behaves very well and is directly pressured onto the hotend.

Side benefit - get a critically damped PID as well.

Here is the table:

{ 256 *OVERSAMPLENR , 0 },
{ 262 *OVERSAMPLENR , 6 },
{ 268 *OVERSAMPLENR , 12 },
{ 274 *OVERSAMPLENR , 18 },
{ 281 *OVERSAMPLENR , 24 },
{ 287 *OVERSAMPLENR , 30 },
{ 293 *OVERSAMPLENR , 36 },
{ 299 *OVERSAMPLENR , 42 },
{ 305 *OVERSAMPLENR , 48 },
{ 311 *OVERSAMPLENR , 54 },
{ 317 *OVERSAMPLENR , 60 },
{ 324 *OVERSAMPLENR , 66 },
{ 330 *OVERSAMPLENR , 72 },
{ 336 *OVERSAMPLENR , 78 },
{ 342 *OVERSAMPLENR , 84 },
{ 348 *OVERSAMPLENR , 90 },
{ 354 *OVERSAMPLENR , 96 },
{ 360 *OVERSAMPLENR , 102 },
{ 367 *OVERSAMPLENR , 108 },
{ 373 *OVERSAMPLENR , 114 },
{ 379 *OVERSAMPLENR , 120 },
{ 385 *OVERSAMPLENR , 126 },
{ 391 *OVERSAMPLENR , 132 },
{ 397 *OVERSAMPLENR , 138 },
{ 403 *OVERSAMPLENR , 144 },
{ 410 *OVERSAMPLENR , 150 },
{ 416 *OVERSAMPLENR , 156 },
{ 422 *OVERSAMPLENR , 162 },
{ 428 *OVERSAMPLENR , 168 },
{ 434 *OVERSAMPLENR , 174 },
{ 440 *OVERSAMPLENR , 180 },
{ 446 *OVERSAMPLENR , 186 },
{ 453 *OVERSAMPLENR , 192 },
{ 459 *OVERSAMPLENR , 198 },
{ 465 *OVERSAMPLENR , 204 },
{ 471 *OVERSAMPLENR , 210 },
{ 477 *OVERSAMPLENR , 216 },
{ 483 *OVERSAMPLENR , 222 },
{ 489 *OVERSAMPLENR , 228 },
{ 496 *OVERSAMPLENR , 234 },
{ 502 *OVERSAMPLENR , 240 },
{ 508 *OVERSAMPLENR , 246 },
{ 514 *OVERSAMPLENR , 252 },
{ 520 *OVERSAMPLENR , 258 },
{ 526 *OVERSAMPLENR , 264 },
{ 532 *OVERSAMPLENR , 270 },
{ 539 *OVERSAMPLENR , 276 },
{ 545 *OVERSAMPLENR , 282 },
{ 551 *OVERSAMPLENR , 288 },
{ 557 *OVERSAMPLENR , 294 },
{ 563 *OVERSAMPLENR , 300 },
{ 569 *OVERSAMPLENR , 306 },
{ 575 *OVERSAMPLENR , 312 },
{ 582 *OVERSAMPLENR , 318 },
{ 588 *OVERSAMPLENR , 324 },
{ 594 *OVERSAMPLENR , 330 },
{ 600 *OVERSAMPLENR , 336 },
{ 606 *OVERSAMPLENR , 342 },
{ 612 *OVERSAMPLENR , 348 },
{ 618 *OVERSAMPLENR , 354 },
{ 625 *OVERSAMPLENR , 360 }

Had been running into a bit of jam lately. For no apparent reason the filament would jam up above the hot end and crap the print.

Found the cause and issue. The filament was twisting and the grooves from the hobbed bolt were binding on the in port to the hot end heat break. The outlet from the extruder body is 4 mm, which did not help the situation as it allowed too much filament play. So, I printed a 4 mm by 18 mm plug that had a 2 mm hole in it. Put it into the extruder output. So far, so good at doing the job.