Friday, May 8, 2015

ProJet 1200: Part 2 - Accessories,and Safety

Just as the Cube3 requires some essential accessories to be used successfully, so does the ProJet 1200.

But, the difference is that we have to find and acquire those accessories on our own.  When it comes to essentials, the list will probably be surprising.  I'll present them in order of priority as I see it.

Latex Free Nitrile Disposable Gloves

Above all else, I would not even open and try to set up the ProJet 1200 without first purchasing latex-free nitrile disposable gloves.

Latex- Free Nitrile Gloves (Image: Harbor Freight)


The good news is that you are probably be better off with the less expensive, flexible gloves rather than heavier guage expensive brands.  Having tried both, I actually prefer the lighter grades one typically finds in the paint department of local hardware stores in bulk.  The ones I now use were just $10.99 for 100.

Harbor Freight sometimes has 5mil gloves on sale at just $7.99 per 100 in either large or extra large.  I prefer the 5mil to the 9mil.

The reason why this is at the top of the list is that the materials used in the ProJet 1200 have the potential to be an irritant to your skin and, for some, may cause allergic reactions with repeated contact.  This is a case of "Better be safe than sorry".

I have found it impossible not to come into contact with the materials in normal use as the build platfor, itself, dips into the materials and is coated at the time of removal.  Gloves are a simple and inexpensive layer of protection.

Protective Safety Glasses

The next must-have accessory is a pair of safety glasses.  Again, it doesn't cost a fortune for eye protection.  Harbor Freight sells safety glasses for as low as $1.49!

Safety Glasses (Image: Harbor Freight)
But, the safety glasses aren't just o protect you from the print materials.  High strength alcohol is used for cleaning parts and you don't want that in your eyes either.  :)

Paper Towels

Yep.  Number three on the list is a roll of paper towels.  OK.  ROLLS of paper towels.

Paper Towels (image: Bounty)


The most important use of the paper towel is to hold one under the print table as it is being removed after a print completes.  The print table dips into the material.  So, not only the printed part; but, the print table, too, are likely to drip material into the bottom of the printer unless you catch it by placing a paper towel under it as the part is removed from the print bay.

Of course paper towels come in handy in the cleaning process as well, as the part and print tray are dipped into two different alcohol baths.  The "Select-a-size" types will probably result in less waste.

Alcohol (70%-99%)

Immediately after printing, the parts need to be completely cleaned of uncured liquid before the final curing takes place in the curing chamber.  This is done with dips into 2 alcohol baths.  I'm using 91% which is available from CVS; but, in a pinch the 70% works.

91% Alcohol (image: CVS)


Each tray does come with its own large alcohol pad to clean the tray receptacle each time the tray is changed.  I also use small alcohol pads to clean the print table before printing.

Two Glass Bowls

The cleaning process involves two baths in alcohol.  I'm currently using two 3" x 5" x 3" Pyrex storage bowls.  The size is up to you; but, they should be big enough to hold the parts and the print table with room to spare.

Pyrex Storage Bowl

There are several cleaning scenarios.  But, each involves first dipping the part into one bowl filled with alcohol and then dipping the part into a second bowl of alcohol.  You can dip about 12 parts before having to change the alcohol.  I my case, I use an ultrasonic cleaning machine and it can hold two of these bowls perfectly. 

Razor Blades

These printed parts are small and so is the support platform.  So, it is very convenient to use a razor blade of the type used to scrape paint off of windows to remove parts from the print tray.

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An Exacto knife would also be useful for removing supports.

Air

It is extremely important to be sure that all the residual liquid material is removed from the part before the final curing process.  Even a small drop hidden in a crevice could blemish the final result.  Compressed air is suggested; but, not at excessive pressures.  I use a hair dryer with a "cool" setting that seems to work; but, I have not created the kinds of objects that might take a bit higher blast of air to make a perfectly clean part.


Non-Essential But Nice:  Ultrasonic Cleaning Machine

When it comes to cleaning parts before final curing you can go the manual route or the ultrasonic path.  I chose to use the ultrasonic method.  Really great ultrasonic cleaners are outragiously expensive.  So, I opted for the budget Harbor Freight 2.5 liter version.  It seems to work quite well; but, I have nothing concrete in the way of comparing results with more expensive options.

Harbor Freight 2.5 Liter Ultrasonic Cleaner.

Two Pyrex bowls, of the type above, fit perfectly in the ultrasonic cleaner's tray.  Fill the tray with water until it's about 1/4" above the level of the alcohol in the bowls.  It's amazing to watch the alcohol in the first bath absorbing the color of the material as it cleans.  Becuase I have little experience with the optimal times for first and second bath, I won't attempt to suggest a time for each.  But, a good place to start is the time suggested in the printer's user manual.

That's it.  That is all the essential accessories that you need to successfully use the ProJet 1200.

But, one final word about why I prefer the thinner disposable gloves over the more expensive types.  One result of printing a hanging piece is that when the supports fail, the part falls into the $48 material tray.  The only way to save the tray is to fish the piece out of the liquid.  Thinner gloves give you a better feel for finding and retrieving the solids in the liquid tray.  Make sure you get it all or you could damage the printer's Z-Axis control or the glass under the material tray. 

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