DIMENSIONAL ART ORG

"Do what you love for those who love what you do"

Revisit to 3D Printing

My last post was concerned SLA type 3D printing. There is a variation to the SLA laser beam where a full frame binary B&W image is projected at full frame for each layer of the print. Two variations of this process exist. One uses a video projector and the other puts the video LCD screen up against the resin tank with a bright UV light source behind the screen.

The process is called DLP (Digital Light Processing) and creates higher resolution 3D prints than SLA and can be done in some systems at much lower equipment cost.

This has changed my mind about the affordability of high resolution 3D printing in my world of dimensional art. I made a business decision.

I have a DLP 3D printer ordered. This new printer costs about the same as two of my FMD (plastic filament printers) That does fit within my budget.

The DLP printer can produce ready-for-investment masters for lost wax casting. That is my purpose for this printer. The full frame image permits printing multiple items at the same time and no increase in printing time. One ring or 20 copies all print in exactly the same time.

I chose a low cost simple machine. Not purposed for a high production rate but absolutely suitable for the scope and amount of work I produce. It will be a great learning tool. I will also be experienced to advise others or make upgrades in this first system.

Most of my reporting on this new tool will occur in my 3D printing website: http://rd3dpds.com. Eventually I’ll post more here, when I start producing dimensional cast items.

SLA Printing

Schematic representation of StereolithographySLA is Stereo Lithographic Apparatus, most commonly called simply Stereo Lithography.

I have investigated this process for use in jewelry making and any other high surface finish 3D printing. The hardware cost has been coming down, but the cost of materials and the finish work such as UV hardening, and support removal are still cost and labor intensive. With enough production need the cost can be reasonable, but it is a system that should be utilized to its fullest extent.

That means it needs full time operation and not occasional utilization.

The process uses a focused laser beam (a) to “paint” the structure layer by layer, on a surface (c) immersed in a polymer solution (b). The light beam partially solidifies the polymer at the focus/surface point. The build platform (e) moves the item (d) away and usually out of the liquid polymer material as layers are added.

The results are usually the ability to produce a very fine, smooth, and accurate surface finish. Post curing and extensive support removal and detailing by hand are required.

Some of the polymer material is suitable for direct used for investing and casting. Other polymer material can be used in the vulcanized or cold process rubber mold making. Then wax burn-out masters can be produced. Many options are available for producing and using the final print output.

The process although high quality is still expensive and labor intensive. There must be a real purpose and plan to make full use of the technology. If everything I made originated in a CAD drawing, The process would be more attractive for the things I create. I would love a “free ride” to play with the process but to purchase such a system, it would have to pay its own way in increased sales.

I currently don’t produce enough jewelry items for SLA to replace my CNC machining. That’s bottom line reality.

Wax Carving No Contest

DSC07167 DSC07168
What hand carving looks like. Three in their cans, one more to go.

A small inventory of handmade wax carvings is accumulating in the studio ready for lost wax casting. The 100 degree Texas weather and non-air-conditioned studio are not conducive to firing a kiln up to 1200 degrees for 10 hours. One casting session was done a few weeks ago when the weather dropped into the 80’s for a few days.

Crying about the Texas heat seems to be a favorite excuse. That’s actually not a serious problem as I am not operating like a “got to get it done” business. However, it’s nice to mix the silver casting along with doing the wax design.

There is a hankering at the moment to do this one-of-a-kind hand carving of the wax. That could be because the hand carving is performed in an air conditioned office area. But it is also more than the comfort. It is a lot of fun to make something entirely by hand.  

Designing with computer drafting (CAD) is also a favorite process in the comfort in the office. But the several CNC machines that do that intricate machine carving are out in the unconditioned shop. Ugh!

Creating by hand the very fine detail that my computer numerically controlled (CNC) machines can produce is not possible for me. That’s why I like using the CAD software drawing approach. With a good drawing, a CNC machine can usually make it. There is a lot of artistic effort and sense of accomplishment in creating the drawings. The machining process needs to be fully understood and exploited. The results are very rewarding.

The hand work is a totally different approach. A sketch is created but never a CAD drawing. It’s just not needed. A picture or a model of what is intend is also useful.  

Sometimes just sitting down and cutting wax usually works but is not a great idea. A general plan is a definite advantage. A good idea with a sketch or picture solidifies where to go, is the best first step.

Working drawings are almost never presentation quality. Not trying to sell the piece before it is made. A presentation is usually SOP (standard operating procedure) for professional high value commissioned work. Someday it may be needed but no demand for commissioned, high priced work exists at the moment. Ha!

Actually, requests to duplicate previous pieces do come in. So far they have been fun re-work and the results ok for both me and the customer. Recently, orders for a whole series of flying horse pendants and pins from one example made on spec for my daughter, came in. Custom ring designs are occasionally requested.

A rubber mold duplication system is available to do wax injection molding with popular repeat designs. It is perfect for use duplicating hand carved originals. A CNC part can be duplicated by running the program again or using the mold process. It’s nice to have options.

Hand work presents or reveals the real artist in me. Every mark or flaw on the wax is there because I put it there. There is considerable enjoyment, to create directly through manual hands-on effort. It is different (and a lot slower) than sitting back and watching the machine do all the perfect cutting.

Having and using both methods is an enjoyable advantage. Some items need, even demand, the cool precision detail of machine carving. Others designs deserve the warmth of fine handmade work.

I am getting better with hand carving. Seeing the outstanding hand work done by others induces a desire to stay involved in quality handmade work. No allowance for my peripheral neuropathy limitations is ever an excuse for poor work. Hand work is just a bit slower, with care how to hold things. Right now it does not prevent carving anything imagined. It’s good for my spirit to work directly with my hands. It’s a type of personal satisfaction felt in creation of the work. Best therapy available.

Machine and hand carving are both rewardable. One method is no “better” than the other. There is no contest between them. So, no winners or losers. Just skills to develop and results to be enjoyed

A Day's Work

DSC06563A day’s work turned into two. I had two investments out of four crack after firing, so I had a bit of a do-over. But this is the result. The rose hearts are always good sellers so I need to keep a few on hand. The ruling lines are 5/16” spacing. Click on picture to enlarge.

The Pegasuses (Pegasii ?) are an experiment. The three little ones are charms or very small pendants. The two larger are definitely pendants. They are Sterling silver but have been acid treated to raise a coating of fine silver. These two pieces will be glass enameled red. They are wearing in-line roller skates. It’s the mascot of my daughter’s Pegasus skating club.

The large tags are an experiment too. The one marked “Adams” is a commission, but I also decided to make a generic “Texas” version. 

Freshly Pickled

DSC06506I love the look of silver when it is fresh out of the pickle. It's all white and pure looking.

Casting of silver causes a fire scale to form on the silver because of the high heat and exposure to air. When a silver piece is released fresh out of the investment material, it is very dark and scally. The first step is to wash and scrub off all the investment, then to drop the piece into the pickle bath.

I use an organic acid solution that it heated to slightly steaming temperature in a small crock pot. This is the pickle. The piece, depending on solution temperature, may stay there for about a half hour or so.

I usually am able to scrub off the blackness about half way through, then a bit more time in the pickle the silver will be the snow white as seen here.

This is actually the pure color of silver before it is polished. The slight pink seen on the metal is a blush of the copper that the acid draws out. Sterling is 7.5% copper to make it hard and more durable than pure silver.

After this stage, the sprue is cut off and filed smooth untill evidence of the sprue location no longer exists. Then comes all the polishing and burnishing to the final finish.

Some pieces have an applied chemical darkening to add contrast.

So after this point is where all the working with silver really begins. I love it!

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