Follow the Directions!

I have good news and bad news.  First, the bad news.

The Bad News.

My precariously built hot end has failed.  It has clogged.

The Good News

The good news is that the failure had nothing to do with the quality or reliability of the RapMan kit.  It was all me.  And, the reason why that is good news is that, hopefully, I can help other new builders avoid the mistakes that I have made.

Mistake #1 - Cutting the PTFE insulator too short.

The directions call for cutting a small slice off the end of the PTFE insulator.  The operative word here is SMALL.  I sliced off a tad bit too much and, from my research about clogging problems, this is DEFINITELY not a good thing.  It apparently allows melted plastic to rise up and cool, clogging the hot end assembly.

I am ordering a new pre-built hot end.  But, I am also ordering a non-built hot end kit so that I can demonstrate the RIGHT way to do it.  At least the RIGHT way is the plan.  LOL!

But, for now, make sure you cut just enough of the material to square the end, taking off as little as possible.  Put that squared off end into the PEEK insulator leaving you enough room to cut it again when you assemble the wooden MDF plate.

The directions were absolutely clear.  I wasn't!

Mistake #2 - Not paying attention to the material type before taking it from the box.

In taking out the material I've been using for the duck tests, I failed to pay attention to whether it was PLA or ABS.  I simply made the assumption that it was ABS.

That meant that I was selecting a test model that was built for ABS, which requires a hotter temperature than PLA.  This overheating also probably contributed to the results I'd been seeing and the ultimate clogging of the hot end.

The type is not printed on the reel.  It is only printed on the box in which it is shipped.

I usually toss boxes immediately.  But, fortunately, I had not tossed it yet.  So, I was able to correctly identify the correct material type.

I'm learning that a perfect build is all about paying attention!  Fortunately for me, Bits From Bytes makes a very high quality product, has anticipated people with my building skills and makes a pre-built hot end available on their store! :)

Bed Level Adjustment - Using the Test Duck

Once the build of the RapMan 3.2 is completed, it is time to try to optimize the print.  This generally involves two critical adjustments. 

• Positioning the bed relative to the hot end (Distance)

• Leveling the adjustable bed.

The most critical adjustment is the one that determines how high the hot end will be relative to the adjustable bed.  This is determined by the 70mm bolt attached to the extruder head.  It is better to start with the bolt fully extended.  Because if it is set too short, you will not only scrape the bed; but, you will melt it as well.  I'll go into this adjustment more fully when I can take some images of the extruder and bolt.

But, for now, I want to concentrate on the effect that an out of level bed will have on your prints.   We'll use the test duck that you can download from Bit From Bytes.

Here is my first attempt at printing the duck using the black filament that came with the kit.  I believe you should be able to see the images at full size by clicking on them.  Forgive the dust on the ducks.  They've been around a bit.  LOL!

Duck Test #1

The duck is printed facing to the left of the RapMan and it looked pretty good for a first print as I was watching it form.  But, when I removed the duck and took a look at the back side, it was apparent that I had a lot of work to do.  But, what was that work?  What made the back side bad and the front side good.

The first hint came as I looked inside the duck.  It's hard to photograph.  But, for each of the missing lines in the above image, there is a strand inside the duck that is unconnected.  The instinctive answer is to raise the back part of the adjustable bed, thinking that the gaps were caused by lack of adhesion.

Duck Test #2

So, using both bolts in the back of the adjustable bed, I raised the back one quarter turn on each bolt.  As you can see, it's better.  But, notice what happened to the raft.  It stuck to the table so firmly that I had to run out and buy a razor blade holder.  Even then I practically destroyed the duck in the process of removing it.

SO... I ADJUSTED THE BOLT ON THE EXTRUDER HEAD TO LOWER THE BED RELATIVE TO THE HOT END

Starting again, and thinking if a little good, then more is better, I loosened the bolts in the back a bit more.  WHOOAAAA!  NOT good, as you can see from the third test.

Duck Test #3

This was NOT due to adjusting the entire bed lower.  It was due to raising the back of the bed too much.
Of course, this prompted me to come up with a better way to level the entire bed before going on to the next test.  I will talk about the method I came up with in another post.  But, for now, it is enough to say that I came much closer to getting the bed level on the next pass.

Duck Test #4

Now, we are getting somewhere.  We are very close to honing in on the right bolt tension to level the bed.  But, as you can see, the back side of the duck STILL has some issues that are not apparent on the front side of the duck.

So, I loosened the back bolts by 1/6 of a turn on both sides.

Duck Test #5

At this point, it loos like we are going in the wrong direction.  But, pushing onward, it seemed like a good idea to adjust just one bolt, since the roughest parts were at the head end.  So, the left bolt was loosened another 1/6 turn.  And, another print was tried.

Duck Test #6

The great thing about this test, is that it made it apparent that bringing the bed up in the back was probably NOT the right solution.  In fact, it seems to be making the problem worse.  So, just before I left home this morning, I took the bolts back to their original position and TIGHTENED the back bolts by 1/6 turn.

We'll see how that works.  But, it is clear that leveling the bed is not only tricky; but, vital if we want to have perfect 3D prints.  And, observing the results above, my thinking is that LOWERING the back part of the best might result in smoother layers after all.  We'll see.

But, there is another observation I'd like to make.  That is the fact that looking at the raft for each duck can tell us a lot.

The raft at the right was created with Duck Test #3.  The black tint comes from the fact that there was some residual black left in the extruder.  The important thing to note with Duck #3 is how WIDE the raft filaments are in comparison with the other rafts.  This is because the hot end was too close to the best for that run.  And, it made it VERY difficult to remove.  By, test 5 I'd realized that the 70mm bolt should be lowered more.  But, the filament is still a little fat.  Test #6, was much better, except for a fat section as the print started.  I'm not sure why that happened.  But, both #5 and #6 were much easier to remove than earlier test runs.  It seems to me that a dedicated post related to what a raft might be able to tell us is in order.

But, for now, the leveling quest is continuing.  Stay tuned for tonight's result!  I've really enjoyed this quest and I hope it is helpful to all those trying to set up a RepRap or RapMan 3D printer.

Refining the RapMan Print and Tool Find

I'm in the midst of refining the quality of the print from the RapMan 3.2.  I will have pictures shortly to show my progress.

I'm using the duck model, that is among the test models to download from Bits From Bytes and it seems to be a great test subject.  I'm consistently getting good results on the side of the duck toward the front of the RapMan and consistently NOT getting perfect results on the back side.  This seems to be a bed leveling issue.  And, I'm chasing that down.

The tolerances are incredibly close.  So, it doesn't take much of a turn on a bed adjustment bolt to send things in the wrong direction.

In the meantime, I found the perfect ball-head hex tools for your RapMan build from a U.S.A. company, located in Colorado called ToolsDelivered.

You'll need 3 different sizes of the BAHCO BALL-END HEX SCREWDRIVER

The three sizes are...

• 2.5mm 
• 3.0mm
• 4.0mm

They work beautifully and are much easier to use than the normal hex wrench.

RapMan 3.2: The Build Experience - Part 6

Now the fun REALLY begins... Calibrating and Fine Tuning the RapMan 3.2 Extreme 3D Printer.

I just finished building a RapMan 3.2 Extreme 3D Printer.  While this image was taken at the 3D Systems headquarters, it is the same model that I just finished building.

RapMan 3.2 Extreme

I first want to comment on the last portion of the build, beginning with the hot end and extrusion assembly.  Up to that point, I gave very high grades to Bits From Bytes on their build documentation.  But, at the most difficult and critical phase of the build it seemed to me that the writer just fizzled out.  That may be due to the fact that the 3.2 version was different than earlier versions.  And, it also may be that because the plastic used in the head assembly is clear that the images are almost impossible to convey the construction adequately.

Whatever the reason, I felt that the last 1/3 of the documentation could be improved considerably.

In particular, the long 70mm bolt that hangs from the extrusion head was not completely explained in a way to could have resolved some of my early issues with the hot end dragging along the bed, melting it.  This was compounded by the fact that the firmware for my machine did not actually use the Z-Offset setting from the control panel.  The Z-Offset setting, when working is the best way to fine-tune the relationship between the hot-end and the bed... once the bed is completely level relative to the X-Y assembly.

Once everything was assembled and adjusted as well as my old eyes, augmented by a magnifying glass, could get it, the print testing started in earnest, using the supplied duck model.

I have spotted some interesting things that I will go into more deeply once I have printed out several test models of the duck to see if I can get it to print evenly on all sides of the duck.  Right now, one side is printing better than the other and it could be bed tilt, belt tension or an as yet unidentified problem.  But, at least we can move on to using the RapMan.

I will say this.  The resolution is better than I expected on the "good" side of the duck.  Now to get ALL sides printing that well!  :)

RapMan 3.2: The Build Experience - Part 5

Rescued!!!

The Thermistors arrived this afternoon.  That was incredibly fast from the UK to the USA.

So, the countdown resumes and I can get back to building the RapMan 3.2 Extreme.

But, I want to take just a few minutes to talk about how pleased I've by the response of Ian and the Bit from Bytes team to my plight.  It clearly was use error.  Yet, there was no hesitation.  They might have been THINKING about that dummy in the United States that messed up the job of crimping the Thermistor leads.  But, if they were, they sure didn't show it.

I received not one; but, several emails of support.  And, I REALLY appreciate that.

Now....

ON TO THE TASK AT HAND!

RapMan 3.2: The Build Experience - Part 4

I crashed and burned at building the Hot End.  And, it had absolutely NOTHING to do with either the quality of the parts or the quality of the documentation.

It had to do with aging eyesight.  And, no kit can protect itself from that.

From reading on the web, I already knew that building your own hot end was THE most tricky part of the build process.  And, when I opened the parts for the hot end build, I immediately understood why.  They are small and they are delicate.  That is NOT a good combination for fat fingers and less than perfect vision.

But, I pushed on, aided by a lighted magnifier.

The first hint of trouble came when my first crimp failed to hold and the smaller of the two wired being mated pulled out.  Not good.  A pure case of operator error and that put me one down when it came to the crimping ferrules.  Also not good.

Fortunately, I was in video for years and have a lot of old parts around.  So, with a little bit of rummaging around I managed to find what I hoped would be a suitable replacement.  I have to say that I thought it was a BRILLIANT idea... even if the part I was trying to use was not exactly like the one I was trying to replace.

But, like many of my brightest and best ideas... especially those I get at the twilight of the day... this one turned out to be just a little less brilliant than first thought.  As I crimped, the thermistor lead broke off less than a 1/4" from the thermistor.  I was dead in the water.

So....

Now, I have a new plan.  This one involves ordering a pre-built hot end.  Now, THAT has GOT to be a brilliant idea.  Especially, since they are not all that expensive.   I'll let some young person, with great eyesight and a lot more experience, put together the hot end that I will count on to do what a RapMan printer is suppose to do.

But, I will not completely cop out.  I hope to be able to obtain a thermistor or two and some ferrules and hop right back on the horse from which I have fallen, just to prove to myself that I can do it.  The worse thing that can happen is that I end up with an extra hot end that may or may not live up to the quality and performance of the pre-built one.

In the meantime, I will move on to the rest of the build, as much as possible, so that when the hot end arrives it's ready to go to work immediately.

You can probably guess that it will be my recommendation to purchase one of the RapMan models that comes with the pre-built hot end... especially if your eyesight isn't what it used to be and/or you have fat fingers!  :)

RapMan 3.2: The Build Experience - Part 3

Back to building!

This time I want to focus on the quality and clarity of the RapMan 3.2 documentation.  It is, in a word, EXCELLENT.

Here, for instance, is the documentation for the laser cut 5mm main panel parts sheet:

Every part is clearly color coded and labeled.  The identification numbering system is very well thought out.  And, differences between the model I have and previous models are also identified by color code so that I would not be looking for parts not included in my particular kit.

Even the contents of the small bag components are well identified by both ID and image.

Moving into the build itself, Bits from Bytes includes an extra touch to help minimize frustration.  They've include parts and instructions to help the builder get the right feel for how to tighten bolts without putting too much stress on the plastic.  Each step of the "Stress Test" is documented as completely and as clearly as all the subsequent build steps for real component building.

This kind of quality documentation is why the build manual is 149 pages long.  They take incredible effort to be clear at every single step in the process.  First there is the overview of the component complete with parts list and the location of the parts on the laser cut sheet.

Next comes a list of the tools that will be required to complete the assembly of the component along with any safety and build warnings associated with building the component.  Note the alert that tells the builder to be very careful about making sure parts are not reversed.

Then comes a step-by-step description of the build process along with images matching the step order.

But, the REALLY cool part of the documentation is the 3D active content that allows you to rotate a 3D model to examine exactly what the finished component should look like from all angles.  Here are two screen captures of a component being rotated.

This is SERIOUSLY useful!  And, it goes a long way to make a sizable project manageable!