Build Plates Rant

I was recently asked to comment on the build plate that I use on my printer.  Specifically, why I use painter tape on the HBP (http://www.3dprintmd.com/print/heated-build-plate/).  I did quite a lot of research on what material to use on the build plate specifically for PLA which I almost exclusively use.  The Information was a bit sparse but I did come to the same conclusion that may others did.  IF IT AINT BROKE DON’T FIX IT.  There are a lot of people out there passionate about the build platform and the treatments.  Anywhere from painters tape to bare glass to acetone dissolved ABS and on an on.  For the most part I print on painters tape because I found that it work.  The adhesion is generally great and I very rarely get warping or pealing.  So you may be asking why bother with the HBP at all.  Well that is an easy answer that is two fold.  The stock build is known to warp which mine almost certainly was and it need replacing anyway.  And the second more important answer is that PLA does warp even though it does so much less that ABS.  I use the HBP on every print and I set it to 45C and I never get pealing or warping.  Yes there are still times that I get a bit of a curl on the edges of some models but it is usually very minimal and most of the time can be eliminated with a closer tolerance on the leveling process.  If I get very careful when leveling I can get the print to stick so well to the tape that it is very difficult to remove and also reduces the life of the tape but in return I get no warping or pealing.

Generally I get great life from an application of tape.  I can get anywhere from 20-30 prints on the same spot with no problems.  Most of the time I end up replacing the tape not because the print is not sticking anymore but because I was bit careless on removing the item and nicked the tape.

I have two plates that I alternate on my printer so that I can have one quickly ready when I mess up the tape.  This works out great when I have a large order since I can keep the printer going while I am replacing the tape on the other plate.

Tape replacement is simple.  I simply take off the old tape which always comes off quite clean.  I would have though that the glue would peal off when heated but I have never had a problem with that.  I then lay out one piece of widest painters tape I could find (3 inch).  I smooth it out paying close attention to not trap any air bubbles and making sure not secure the center seem edge.  I then layout another price and very carefully butt the tape in the center leaving no transition.  This take a lot of patients and practice but when done right the seem is barely discernible on your prints.  Luckily the build plate is exactly 6 inch wide so two pieces works perfectly.

I would highly encourage anyone that is printing with PLA to try painters tape first.  If you are not satisfied with it then by all means try something else.  Please remember however that the number one reason for pealing and warping is not the build plate material, it is the leveling.  Re-level the bed and try again.  Please keep in mind however that there will be some models that will just away warp based how the density of material changes within the model.

I will say that I may move away from painter tape eventually.  I backed the Gecko Tek Build plate http://www.geckotek3d.com/ quite a while ago but have yet to take delivery due to complications.  I am waiting for the ABS version since the PLA version (which is available now) does not hold up very well to a HBP.  Time will tell if it can outperform the time tested and gold standard that is known as Blue Painters Tape.

One last question I got was about printing on rafts.  I don’t have much to say about them since I never use them.  I have never had a need to use them since I get such a great performance from painters tape.  It would seem to me that all the problems that the raft is intend to solve can be resolved by better bed leveling.  Or if you are unfortunate enough to have a warped bed; its time to replace it.

Well enough of this rant.  I hope I answered all your questions Andrew.  If not please add to the comments and I can try to answer them the best I can.

Also I am aware of the http://shop.raffle.ch/ site for upgrades.  They are quite nice but I have yet to have the need for theses parts.  I was looking for a time to upgrade my rep 2 to have a dual head but since it would cost around $500 I think I would rather put that money toward a newer printer.

Friction welding: Effective and Fun

Awhile ago I say this article on Hackaday http://hackaday.com/2014/12/30/3d-printing-technique-friction-welding/ on how to quickly and easily use friction welding on 3D prints.

I recently printed out a model of the Hubble Space Telescope to honor 25 years in space.  http://nasa3d.arc.nasa.gov/detail/HST

20150424_210407

The print was in several pieces and it need some assembly.

The technique is quite simple.  Put a piece of filament into a Dremel and push it into a joint.  You will need a smaller collet as the default one is too big.  I happened to have one from a set I purchased years ago.  Insert the filament with about 3/8″ sticking out.  Don’t worry if its not exactly straight it will fix itself with a little pressure.

20150503_151050I ran the speed on the Dremel at 3-4 which seemed to work fine for me.

Here is before: 20150503_151159And after:

20150503_151309Here are some more joints:

20150503_151210 20150503_150848

It works great it is quite easy and it seems to form a great bond.  Be ready to stop the Dremel and pull more filament out especially when you are filling a big joint.

 

 

 

Poor Mans Dual Color Prints (With one Print Head)

So what are you to do if you have only one print head like my replicator 2 has but you want to print two colors?  Some may give up and say “ya just can’t”.  I have already show that is not entirely true.  Remember my two color business cards?  http://www.3dprintmd.com/print/printed-business-cards/

Ok well some may say that this is cheating and this is not really two color printing.  It is merely using z-stop and changing colors.  Ok fine I get that, and I was not really satisfied with it either.

Lets take this concept one step farther.  How about printing around another object instead of on top of it?  Turns out, yep, you can do that that too.  It turns out to be relatively easy but with a ton of caveats.

First a word of warning.  If you do not pay close attention to what you are doing you could damage your printer.  Printing on top of another printer is not recommended for the inexperienced and it could cause your print head to crash into the first print or worse strip a belt or cause other damage.  I am not responsible for if you break your things.

Now with that mombo jumbo is out of the way…

Here is the goal:  I am printing a case for a usb adapter for the Old skool Sidewinder Joystick (http://www.descentbb.net/viewtopic.php?f=8&t=19061&sid=3da4f9e4089d6418b7a500aeab2aaa0c&start=160)

We didn’t want just any old case naw, that would be too easy.  How about one with a logo inlaid into the top.  Wells that’s easy enough if you have a two head printer.  But you only have one print head?  Well then challenge accepted!

Whats the problem you say with just printing one piece then printing another around it you may ask?  Well the problem comes when the second piece is printing the slicing engine does not know that it should not crash into the piece already printed.  Its needs to stay out of that area but there is no way for it to know how to do that.  It turns out that there is a happy accident awaiting to be discovered.

First prepare the model.  This is easy enough.

top

Top With .6mm deep hole in the shape of the logo

Justlogo

Logo .6mm Thick

logo

Top and Logo aligned

I have only done one of these and it is possible that I just simply got lucky with the design.  The design needs to be simple and should not have any holes in the middle of it.  Other design limitation may exist but I have not done enough of them to know for sure.  The design will play out in the next several step to see if its a viable option.  Please note that the inlay is exactly .6mm thick.  I will be printing with .3mm layer height and this will amount to exactly 2 layers being printed.  I would NOT go any higher than this.  The nozzle is an upside down cone shape and therefore gets bigger the farther away from the build pate you go limiting how close you can get to the first print.

Set up the slicer.

Here is what NOT TO DO and the reason why

Makerware is not an option for printing since the tool path algorithm likes to use any empty space round the object being printed.

If we slice with makerware there is nothing you can do to get the travel moves to not cross into what would already be printed.  Remember that we will be printing the logo first and the box around it must not cross into the logo area.  Otherwise, the print head will crash into it.

Makerware is a no go.  Travel moves cross into the logo area.

Makerware is a no go. Travel moves cross into the logo area.

So what can we do instead? ReplicatorG to the rescue.  I know what your are saying ugg not RepG that thing is so hard to understand and confusing.  Yea I get that too but in this case there is a happy accident in the slicing engine that is going to save the day.

It turns out that when RepG slices it tends to only follow the perimeter (in this case interior) of the object when doing travel moves.  Why it does this is somewhat of a mystery to me but, at least for this object it works out perfectly.

First edit your slicing profile to show the tool paths (or to make it easy you can copy mine. Replicator 2 – 340 micron)

In order to make sure that the travel moves don’t go where they should not go.  Go to the Craft tab and activate Skeinlayer

Activate Skeinlayer

Activate Skeinlayer

Then go to the Export tab and enable Analyze Gcode

Analyze Gcode

Analyze Gcode

Now when you slice you will get a Skeinlayer popup.

When you open you stl files make sure that if you change the location on the build platform you make the exact same changes to both the logo and the top.  These parts must be exactly aligned.

VERY IMPORTANT Pay very close attention to the grey lines.  These are travel moves and the MUST NOT cross into the Logo area.

Layer #0. Check All layers with the logo in it

Layer #0. Check All layers with the logo in it

Layer #1. Check All layers with the logo in it

Layer #1. Check All layers with the logo in it

Layer2.  The logo is gone since it was only 2 layers .6mm tall

Layer2. The logo is gone since it was only 2 layers .6mm tall

Now that we have the top sliced we can slice the logo with the same settings then print.

First load the logo color and print the logo as normal.  I am using the wipe in my profile so I need to peal that away before the next print.

Logo printed

Logo printed

wipe removed

wipe removed

Now change filament colors and print the top.

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Print complete and it looks great.  The bond is amazing.  It looks as of it was printed all in one piece.

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Here is black on red

20141215_23032720141221_124028

Wow that was a long post.  Thanks for sticking with me.  Hopefully I have proved that you can do two color with a single print head.

LED lights – Auto off after 0-3 minutes – Update 1 of 2

I have a two year old and she likes to play inside one of the kitchen cabinets.  I would imagine that it gets dark in there when she closed the door, so I decided to puts some lights in there.  Being a 2 year old she likely to burn through some batteries so I though I could do a bit better than a simple on/off switch.

To be honest I have been wanting to do something with a 555 for a long time.  I picked one up from Radio Shack back in January 2003.  Now there is a need, so now is the time.

I basically used this article as a basis http://www.instructables.com/id/555-Timer/?ALLSTEPS.

I easily had all the parts so it was just a matter of assembly.

I will be using the 555 in the mono-stable mode circuit.

FSYCYIOH799760K

The only differences I made is that the control resistor shown here as a 10k ohms has been replaced with a 500k potentiometer/preset and the control capacitor shown here was replaced by a 330uF cap (since that’s the closest I had).  These values workout to a timeout of 0-181.5 seconds, right in the range that I was looking for.

In this case I also decided not to go all out and do a circuit diagram an etch a PCB.  This is a simple enough circuit I can just use some perfboard without the fuss.

Here is my result. 20141130_205152

It actually came out quite nice.  It has one button that starts the timer and turns on the 3 white LEDs.   The button does on nothing while the lights are on so in order to keep them on you have to hit the button every time they turn off.

 

LEDs stand off the board for max dissipation in a case I will make next.

LEDs stand off the board for max dissipation in a case I will make next.

Bottom side

Bottom side

Massive 330uF radial cap and an 805 10pF cap under it.

Massive 330uF radial cap and an 805 SMD 10pF cap under it.

This will be powered by a 9v battery which will hopefully last a while at 2min duty cycles.  I am not sure what the current draw is when idol (I may measure this later) but I think I will add an on off slider switch.

The next step is to make a case.  I have some ideas on what I want to do with the case but I do know that it is going to have to be rugged enough for a 2 year old to be pounding on it every 2 mins.  I was thinking that would be similar in design to the staples easy button but I will see how that pans out.

That’s all for now hopefully I can get the case done soon and I will post the second update to this post once it is done.

Fuse – Welding filament clamp for 3D printer

Back in July I back a project https://www.indiegogo.com/projects/fuse-welding-filament-clamp-for-3d-printers.  This looked like a neat idea.  Basically it has a heater in the center of a Teflon block and a 1.75mm hole in it.  20140707025312-Slide_1

You put one end of filament in one side and another piece in the other push it through and it welds the two pieces together.

I received my Fuse today.  Here is what I got.

20141114_211810 20141114_211819 20141114_211901 20141114_211913Overall construction is good, no issues there.  It looks well machined and assembled.  Of coarse the next step it to plug it in an give it a try.

This is my first attempt.  It looks  pretty ugly.  The filament squished out into the slit around the 1.75mm channel.  I had the screws tightened by hand the best I could.  I did not try tightening them with pliers since I did not want to damage the thumb screws.

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Needless to say its not idiot proof as it take some getting used to.  Eventually after some practice I did start to get some usable joins.  This is one of the better ones that I was able to do.
20141114_222657

Same join as above compared to another one that is poor.  You can see that the white part is bulged out.  20141114_222733

Initial reaction based on 1 hr of use (yes I know that hardly makes me an expert).

The idea is solid;melt the ends and jam them together.  This is a bit more challenging to pull off than you might think.  To be fair I am using PLA which is probably the most difficult material to work with due to its low glass transition temperature.  I found that the melting was difficult at best to control.  PLA just loves to melt and deform as I learned from my experience with the http://www.filastruder.com/.   This does not mean that I don’t think it can work.  It does take some practice and lots of retries but with time I think that I can do much better.  Unfortunately, due to its difficulty of use (right out of the box with no experience) I don’t think that we will see  wade spread use of this product.

My next step will be to make some multicolored filament and do some printing with it.  I am somewhat concerned with how the printer will handle the transition, especially when the filament is not perfectly consistent in diameter.  From everything I know and read I dont think its going to be a big deal, assuming that there are not any bulges that make the filament jam in the hot-end.

More post on this topic to come.