Sunday, September 23, 2012

A new filament feed for the UP!

My UP! came with a 800 gram reel of filament.  I also bought thee 1 kg reels from the Delta people along with the UP!  Not long afterwards I bought a rather large spool of ABS filament from my usual supplier and had been putting it onto the empty 800 gram reel as I needed it.

This spool to spool transferring was a bit of a pain so when I bought a large consignment of ABS from New Image I had them put it on their own 1 kg reels.  New Image reels looked nothing like Delta's and would not fit onto the UP! spool holder, so I new I was either going to have to print a new spool holder or continue reel to reel transferring.

I was in a hurry with a mechatronic hand project, so rather than use the New Image spools I just unpacked one of my Delta spools instead.  Imagine my surprise when I discovered that the 1 kg Delta spools won't fit on the UP! spool holder, either.  Totally shocking.

In any case, I went down to the hardware store, bought some plywood, a large diameter bolt and a Lazy Susan turntable assembly.  Here is the new spool holder that resulted.

It works beautifully with both my wide New Image spools and also the 1 kg Delta spools.

Thursday, June 14, 2012

Is Reprap UP! to the Chinese challenge?

It appears that Delta Micro's UP! and UP! Mini are aiming to be a serious threat to Reprap and other personal 3D printer offerings in very short order.

Some months ago, a long term technology friend of mine acquired an UP!  While Peggy has been a inspired developer of educational technology for years, she did not, to the best of my knowledge, have any prior knowledge of the ins and outs of 3D printing on personal printers.  In spite of that, Peggy whipped her UP! printer out of the box and did a brilliant print first time out. That really caught my attention.  I'd been working on the Reprap project for years and still, when I bought a Rapman, a greatly enhanced Darwin-derivative, several years ago it had taken me the better part of a month to get used to the quirks of printing on it to the point that I could get reliably good prints.

The UP! 3D printer by Delta Micro

At the time I had abandoned my effort to build a second generation Darwin-derivative printer as simply taking too much time and getting in the way of other design work I wanted to do.  My Rapman, however, was getting a little long in the tooth and, should parts break I would not have the means to print replacements.  Clearly, I needed another printer.

I had been idly interested in the UP! for some time.  Delta Micro, which makes the UP! is the Chinese equivalent of Stratasys here in the US.  Some years ago, I suggested to Stratasys that they leverage the highly sophisticated solids model processing app that they supply with their high-end printers to promote a inexpensive, personal 3D printer in the Reprap price range.  To Stratasys' credit, they eventually did introduce such a printer that they marketed though Hewlett Packard.  Unfortunately, their price point, which was around $14K, was well beyond the means of most pocketbooks for personal use.  Delta Micro, on the other hand, did leverage their high-end solids model processing app to promote their own personal printer, the UP!.  The UP! was priced at about $1.5K, roughly the same as my Rapman costs currently.

After much agonizing about abandoning the Sampo printer I'd spent considerable money in developing, I went ahead and purchased an UP!.  My notion was to get a close look at it to see how much of what Delta Micro said about it was true and how much was hype.

Out of the box, one thing that immediately struck me was the tiny size of the UP! The 140x140x135mm print volume reminded me a lot of the old Makerbot Cupcake.  It took me about half an hour to get out of the box and set up, ready for operation.  While the manuals indicated that I might have to level the print surface, this was not necessary.  Calibrating the printhead height took about ten minutes.  When I ordered the UP, I was very worried about print adhesion to the print surface.  Delta Micro offered three solutions; perforated printed circuit board, painted glass and Kaplon tape covered glass.  I had had so much drama with prints peeling off of the print table with the Rapman over the years that I ordered all three options.

As it turned out, I need not have bothered.  The simplest option, perforated printed circuit board, clipped onto the print table with standard office clips,  has proved perfectly adequate.

Printing on perforated printed circuit board

I had been assured by the American distributor that the UP! had a heated print table.  It certainly didn't look that way out of the box.  The black iron print table is heated by a central heating element in the middle of the table.  This arrangement struck me as dubious.  The control app that goes with the UP lists the table as heating to 105 degrees C.  I was worried about the temperature gradient of the print table and did a bit of thermal imaging.

Thermogram of the bare printer table

Interestingly, the thermal gradient between the center of the table to the edge was only about 5 degrees.  When I laid the perforated printed circuit board over the print table, I got about a 10 degree overall drop in the print surface.

Print table with the perforated print circuit board

The addition of the board evened out the print table temperature quite nicely so that there was very little in the way of a gradient from the center of the table to the edges.

Construction of the UP! was quite simple.  The enclosure is basically stamped sheet steel.  Positioning is done with stepper driven belts and flat plate linear guides with grooved edges.  It is very simple and very robust.  I found out how robust when I accidentally knocked the UP! off of the stool it was sitting on in the first picture in this article.  Horrified, I picked it up and could see no damage.  With considerable dread I restarted the printer and discovered that it hadn't even been knocked out of alignment.  It had fallen about 80 cm onto a linoleum covered floor.  This is not something I'd recommend be made into a regular practice, mind.

While the UP! uses an SD card like the Rapman, it is permanently mounted on the controller board. You load the card via a USB link to your computer and start up the print.  After the print is started, the printer no longer needs a USB connection to your PC.

As I mentioned earlier, one of the original attractions of the UP! was that it had leveraged the software app from Delta's high end printers.  I was especially struck with the sophistication of the structural support capabilities reflected in this picture.

Teapot printed on the UP! with breakaway structural support

One thing that I noticed about the UP! was that I had far less trouble printing tiny objects than I had with the Rapman.  The UP! is a bit different than Reprap machines in that it extrudes ABS at 270 C rather than the usual 235 C that the Rapman allows.  The thermal footprint of the 1.7 mm filament extruder is much, much smaller than the extruders that I've had experience with it the past and rather looks like the one that Adrian Bowyer, the father of the Reprap project, designed for the Reprap Huxley machine.

Delta had one picture, since removed from their website showing how you could stack objects on top of each other spaced a centimeter or so and the support capability of the system would print them quite nicely.  Frankly, I had severe doubts about the ease with which print rafts and structural support could be removed.  Experience with the printer, however, has proved those doubts to have been unjustified.

As an example, I recently printed parts for a hand movement sensor for a haptic telepresence robot on the UP!  You can see here a particular print positioned in the print volume.

Finger rings for a hand motion sensor as seen on the UP! solids processing app

Printing the support structure of the rings

Completed print

Support material removed

I was able to recover the printed rings from the support material and clean them as you can see here in less than a minute without hurrying.  When Delta says breakaway support material, they aren't joking.

One of the apparent drawbacks of the UP! is the implication that it only uses Delta supplied polymer.  At roughly $25/lb, it is a bit pricey for an old Scots-Irishman like myself, so I inquired if using third party filament would void my warranty.  I was told that I could use whatever I wanted in the printer, but if I burned out or otherwise damaged the extruder it cost less than $300 to buy new one.

One thing that created a problem is that the UP! uses 1.7 mm filament whereas the standard for Stratasys and an increasing number of Reprap machines is 1.75 mm.  Fortunately, I have a good working relationship with Jim Waring at New Image Plastics.  I have had good results using his 3 mm filament in the past and was able to get him to extrude several pounds of that polymer in 1.7 mm diameter so that I could try it out with the UP!.

The last exercise with the finger rings was done with New Image filament.  There appears to be no substantial difference in print quality between the ABS polymer which he makes, which is manufactured in Taiwan and what Delta supplies with the UP!  Jim's filament, however, sells for $9.95/lb rather than $25/lb, a considerable savings.

Finally, it appears that Delta Micro is going for the throat of the manufacturers of Repraps in the US and elsewhere.  They are now offering a slightly smaller printer, the UP! Mini! with a 120x120x120 enclosed print volume which uses standard 1.75 mm filament for less than $1,000.  The UP! Mini appears to be a serious challenge to both the Reprap variations and to the 3D Systems Cube system.  It strikes me that unless the quality and ease of use of UP! competitors makes a rather quick quantum leap they could easily find themselves to be a historical footnote in the history of 3D printing rather than a new paradigm of virally diffused technology.

The UP! Mini

Saturday, May 12, 2012

Bought a Chinese UP! printer

Got my 3D Up! printer running.  There was some drama with installing drivers.  The manual instructions were written for Windows XP and I was using Windows 7.  Slightly different way of doing things which I managed to puzzle out.

Tested the extruder.  It prints at 270 C.  Now I understand why they designed the extruder head the way that they did.  You'd be hard pressed to print at that temperature with a Reprap extruder head.

Friday, December 16, 2011

Solving a nagging question about print adhesion

Unlike most of you, I don't use an electrically heated print surface.  Some time ago I bought a Rapman 3.1, which used an acrylic 3 mm print table.  I soon discovered that 3 mm was far too thin and quickly warped beyond use.  Switching to 10 mm solved that problem.

After a long time of successful prints, I noticed that with winter causing colder temperatures in the print room I was having more and more trouble getting my prints to stick to the acrylic.  I tried cleaning it and sanding it with little avail.  Electrically heated print tables were just coming available but insofar as printing was concerned, I thought that things were already complicated enough without adding that sort of equipment to my Rapman.

I had an IR heat lamp in the lab, detritus of another experiment, and discovered that using it on a tripod to raise the temperature of the acrylic print table above 40 degrees Celsius measured with a non-contact IR thermometer gave me consistent adhesion.  I soon discovered that I could turn off the IR lamp after 4-5 print layers with no ill effects.  It was not needed for the rest of the print.

The rig looked a bit like this...

Note that the lamp is placed at a 45 degree angle to the acrylic print table.

I soon noticed that adhesion at the near side of the print table was much less firm than that at the back and less firm at the left side than the right.  I attributed this to various things, uneven heating being one of the possibilities.  While the left/right difference made sense the front/back difference didn't seeing as the IR lamp was aligned with the left/right axis.

Cranking the terminal heating temperature before starting a print to about 50 degrees solved most of the problem for the center of the table and I was able to print along the front/back axis with reliable success.  Unfortunately, the back side of the print area seemed to have the print pad melting into the acrylic while the front side would separate easily.

It made no sense.  I thought for a while that it had something to do with the acrylic plate and rotated it with no effect.  Swapping ends and sides always left the back side of the print table very firmly attached to the print pad.  While that wasn't a horrible situation it was annoying, because it meant that processing the printed objects after separation became more time consuming.

A few weeks ago, I purchased a FLIR E30 thermal imaging camera with the intention of learning more about what was happening with prints as they were being laid down, the ultimate goal being building in advanced heuristics into my Slice and Dice app which converts STL files into Gcode.  I also had hopes about eventually doing some research into what actually happens thermally with extruder hot ends with the notion that I might be able to design a better one.

Yesterday, the E30 arrived and I decided that a good beginning exercise might be to look at the distribution of heat on my acrylic print table when I used the IR lamp in its standard configuration to heat it.  The results were quite unexpected.


The lamp put down a marked hot spot at the upper right rather than at the right as I expected.  The upper right was exactly where I had the most trouble with print pad melting.  Obviously, the IR lamp did not give even heating when tilted but overheated in on the upper right.

This was nasty.  I had previously thought about using several smaller IR lamps at the corners of the Sampo printer that I have been developing.  If the smaller lamps behaved like my single, large one, however, this might not be a good idea at all.

I then got to thinking about how IR lamps are actually used in food heating cabinets.  They are almost always placed point straight down.  I rearranged my tripod to place the lamp almost vertically over the acrylic print table.

That sorted out the temperature distribution problem...

Tuesday, August 16, 2011

Sampo's touch screen begins to work...

Adriaan has been working hard learning the TFT programming protocols and has his first touch screen menu working on the Sampo controller board.