Trying Something New

I brought my new mirror design into the shop today however everyone seemed to look at it and think "why are you wasting time on this?"  They don't live with the D2 on a daily basis and I feel the owners might appreciate having elements of the car made to be at least 'on par' with what they have in their standard everyday drivers.  Rather than dissuade me from continuing to design parts to improve the D2 (and other cars really as this can be universal) this just could be the start of the Palatov D2 aftermarket.  

This leads me to this post.  After thinking about how I could attach the mirror to the D2 I decided to try something a little crazy (or so it seemed as I haven't tried this before).  I designed a two piece part which is typically bad practice in CAD since most parts are manufactured separately and makes them rigid in an assembly however, since it will be 3D printed, the printer really doesn’t know or care that it is two separate parts in one file.  

I wasn't sure if this was going to work but after making a quick test print to see if it was even possible I am impressed with the results.  It didn’t quite work as the 'cup' didn’t engage the ball enough so I made one minor tweak to a dimension and am running a second print.  The idea here is the bolt attached to the mirror itself offers basic up and down adjustment while the ball provides adjustment in all axis.  To prevent things from slipping the cup will tighten down on the ball creating friction and hopefully preventing things from moving around.  In this case the layers from the 3D printing process may be advantageous as they act as serrations to help lock everything in place.  We'll see how it goes!

Weekend Project

This weekend I've been working on doing more prototype parts for the future Palatov Rev 2 D2.  Rear view mirrors have been a challenge since D2 owners want to have maximum visibility on track (and on the street) which typically means a big mirror, but the mirrors we've been using have frankly been pretty terrible looking and more or less just tacked on as an afterthought.  Their range of adjustability is generally poor to nonexistent being the result of bending metal tabs that attach the mirror to the roll hoop or where ever is convenient.  

I think I can do better, so designing around the existing "favorite" mirror we've been using in the most recent D2's I created an enclosure that the mirrors glass can be attached to (I'm thinking adhesive foam to dampen vibration and contour around the curve of the glass).  I also added a light because it seems people get really upset when basic features of every car is omitted.  The total price for my mirror enclosure is less than 10 dollars (plus 8 hours of print time).  

On a side note this is the largest thing I've printed thus far and the Taz 5 printed it just fine.

I think I'm onto something!

Perhaps the World Isn't Ready for Dual Extrusion Printing?

One of the big reasons why I decided to upgrade to a Lulzbot Taz 5 was to be able to add a dual extruder.  I figured it would be a great way to add accents to printed objects and open up some new doors in creative design.  This however proved to be just a dream.

Admittedly my first few prints (weeks ago) turned out great.  It only took a few days for things to degrade in very mysterious ways.  The first print that showed problems was a shift knob for the D2 that had a section in the middle that was printed sporadically.  Then things got worse with prints barely being able to start without the extruder becoming jammed, clogged, or just plain failing to extrude filament.  Since my printer works just fine with the single extruder tool head I figured it had to be the extruder and had it replaced under warranty.  

After waiting a week for a new tool head to arrive I thought my problems would be solved.  To my disappointment the new tool head exhibited the same problems.  After sending countless emails to the Lulzbot Tech Support (who are great people by the way!) both before and after getting the tool head replaced, I still have yet to get the dual extruder to complete a print reliably and consistently.  

The tech support people have had me tweak settings, temperatures, tightness of the idlers that keep tension on the filament.  In one experiment where I swapped filament from one tool head to the other the problem seemed to follow the filament leading one to conclude that the filament is to blame.  I replaced the filament with another brand of the same color, the problem still occurred.  So if it is the filament, it would be silly to only be able to use very specific colors and batches with the dual extruder tool head.  

One possible cause of the problem would be what is called "heat creep"  which as I understand it, is the effect of heat moving up into the filament and parts of the extruder where having heat is undesirable.  This is prevented by having a heat sink on the hot end that helps keep the heat down near the nozzle where it belongs.  My prints were less than 19 minutes long however and tended to fail about 10 minutes into the print.  So if it is heat creep, there would be little hope that the dual extruder would be able to complete larger prints reliably.  

An additional problem with the dual extruder is it is inherently messy and yields lower quality prints due to the increased mass of the tool head.  Slowing down the movement of the tool head could help improve quality along with additional tweaking but slowing the tool heads movements can contribute to greater "heat creep".  

In the end I have decided that its best to continue to use the single extruder tool head and simply find other ways to add color to prints.  Print quality with the single extruder is great and it seems to be very reliable with a multitude of materials.  I don’t know if there are people who actually have success with the Taz 5 dual extruder, I’m sure there are.  When I suggested it might be a firmware issue they found firmware wasn't actually available on their website for the Taz 5 dual extruder V2 (the current model) which is concerning.  Perhaps I'll give it a try again when they have the "dual extruder V3".        

D2 Front Body Ready for Molds

The D2 Rev 2 front body is complete and ready to have molds taken from it.  I was able to finish a day early (Thursday) which allowed us to deliver it to the company that will be creating the molds on Friday.  

Next will be the rear section of the car.  It's already got some Duracoat and some sections have been pretty well sanded so it may only take a couple weeks to complete.  While we have had the new bodywork in the shop for the better part of a year, there hasn't been much drive to get them polished.  Last week however we received a down payment on a D2 that will be using this new bodywork so the clock is ticking.  We have one year to get the new bodywork and build the car, but it's going to be a pretty special D2.  The owner (same people who bought the D4 Turbo) love power and want this car to start out at 700 horsepower, possibly more.   Should be pretty exciting!

Sector 111 Drakan Driven by Jay Leno

I remember as a kid seeing Jay Leno's garage of cars.  I never thought I would build a car that would be driven by the man and featured on his show.  

Palatov Rev 2 D2 Bodywork Moving Along

For the past couple of weeks I have been splitting my time between machining parts for the next five Sector 111 Drakan cars and trying to do finishing work on the new nose section of the D2 bodywork.  Applying what I learned from completing the door molds has made the nose progress quicker than any other part.  

Starting with a rough sanding of the raw foam mold to knock down any tool marks I then applied a thick coat of Duracoat primer by brush.  This was then roughly sanded back with 80 grit and 220 then a second coat was brushed on and sanded back with 220 to leave a surface that had no major defects.  At this point duracoat was sprayed on in a thick coat and sanding with 550 commenced along with the addition of surfacing bondo for filling in the smallest of surface imperfections.  The mold has now been sprayed a second (and hopefully the last time) and is being finished with 550 and 1200 to remove the scratches from the 550.

By the end of the week I am hoping to have everything polished and perfect ready to be handed off for the second stage of mold creation.

Dual Color Print Improvements

I ran a couple of "medium" quality prints over night to test my most recent configuration settings and I'm pleased with the results.  There is still room for improvement and some tweaking here and there but I have to admit, its pretty cool being able to produce parts with two colors.  

Dual Extruder Up and Running

I spent lots of time this weekend tweaking my Taz 5's setup with the new dual extruder.  I pulled out all the stops and leveled the bed with the touch off gauge from the shop.  That made everything much easier and helped improve print quality tremendously.  

I ran into some issues with software and hardware.  It turned out that the Simplify 3D software did not work for me at all.  I didnt actually make any progress printing until I ditched the very expensive software and went back to Cura.  I am not sold on it.  I also subsiquently ran into issues with solidworks on my computer.  It would take several minutes to start up and would just hang.  I ended up resetting windows and starting essentially with a fresh install.  The SSD in my laptop made installing everything super quick and by lunch time on Sunday Solidworks was working again.  

A full day and a half of tweaking hardware and software settings eventually resulted in successfully printing the checkered octopus.  As you can see previous prints had quality issues and generally didnt work.  I also ran into some challenges with exporting .STL files from solidworks and having them mate up properly in Cura.  It seemed the origin would change and they wouldnt go together right despite being made from the same part.  I eventually figured out what was wrong (turns out I just needed to tick a box in the export settings, typical simple solution to an annoying problem in solidworks) and successfully created and exported my design for a Palatov D2 shift knob with the Palatov Dragon contrasting with the rest of the shift knobs color.  Hopefully it turns out as great as it looks in the computer!

Modular Mill Soft-Jaw Rev C Ready for Testing

My modular soft-jaw project has been going through some fairly extensive testing this week at the shop.  While I had intended for it to only be used in light clamping tasks where a part just needs to be located, my co-workers have attempted to use "Rev B" for other tasks such as power tapping parts.  There was some cracking and crunching sounds but ultimately they survived and continue to work well.  

Rev C addresses several areas where improvement was needed;

Soft-jaw flex (a result of having to design in lots of wiggle room since my Printrbot doesn't print part ID's very accurately) has been significantly reduced (or possibly eliminated) through adding an interlocking dovetail and tightening tolerances (which the Lulzbot has no problem with)   

Eliminating soft-jaw delamination which occurred as a result of  excessive flex and too thin of a shell/too little infill.  The soft-jaw and insert now has a 2mm shell all around and 80% infill to allow some 'give' but make everything more robust.  

Increase longevity of insert through increasing shell/infill as well as designing inserts for various part diameters.  Currently I have one "v" groove insert, as well as round inserts ranging from .75" to 1.25".  Print time for each insert is approximately 1 hour so creating more inserts to suit different needs is not a problem.

3D Printed Business Cards? Why not?!

It seems engineers like to joke about turning junk parts into business cards that they can hand to customers and clients for fun.  I decided to try 3D printing business cards.  Its fun, novel and sure to get someones attention.

Rev A was a little plain but more a proof of concept.  I had some fun with Rev B, the gears really make a statement and I like having parts stand out off the surface with some elements that cut through the card.