High Speed Finishing

High Speed Finishing

There is an old axiom; “Time is Money”. When working with precious metals; this axiom aptly applies. Process time of jewelry products equates to a time-cost-of-money calculation. The higher the metals cost and the longer the process time, the more cost to the manufacture. High speed finishing shortens the process time to manufacture products.

For high speed finishing; G&S Jewelry Mfg has a large model HZ-120 Centrifugal Barrel Tumbler manufactured by Mass Finishing, Inc. (MFI) of Howard Lake, MN. This system has four sealed tubes that spin in a planetary system very dynamically. So much so that it can reduce a typical two day tumbling cycle to less than 7 hours.
 

Handling Issues

However, the size of the system presented some issues with handling small parts with intrinsic high value. This was most manifest with unloading the tubs after tumbling is complete. We made contact with the technical team at Mass Finishing to solve this issue. They suggested an elegant solution to our problem.

Solution

A sealed insert canister was their solution.  The frame around the canister could be securely inserted into each tub. The parts, media and solution would be loaded into the canister. A pair of “o” rings seal the plug in place. The pictures below show these attributes in detail.

Insert Horizontal 300x225 High Speed Finishing
Sealed Insert Canister With Frame

Maintaining control of the parts is easy with this design. Opening the canister and removing plug makes for easy emptying into rinse basket.

Insert Upright 300x225 High Speed Finishing
Insert Canister Sealed After Loading

The canister is placed in the tub and the cover of the tub locked in place. The frame is held tightly under the tub lid. The frame is clamped securely between the lid and the lining of the tub.

 

Insert Installed 300x225 High Speed Finishing
Insert Canister Installed In Tub

 

Operation

Our system has four tubs. Tub loading is sequential. First the tub marked “1” is unloaded.  Similarly, the tub marked “2”; second and so forth.  Tub tracking ensures that system balance is maintained. This in fact will minimize vibration. Furthermore the MFI system has an excellent jogging control function. This reduces the loading time between tubs. Before long, the system is fully loaded. Finally the safety lid is lowered and locked in place and the system started.

Meanwhile when system is running, previously unloaded material can be rinsed. The canisters are then reloaded and prepared for the next lot to be finished. That is to say having multiple canisters in back of those operating increases throughput dramatically. We believe a second complete set besides the set in the machine to be perfect for handling long runs.
 

Results

After the parts were removed we compared to our previously tumbled samples. The results were exceptional. To clarify; the tumbling time will vary depending upon the process step and finish requirement. First stage is cut media, followed by a second stage of burnishing. Lastly a third stage of ceramic media to deliver a mirror finish.
 

Summary

To sum up; the use of these canisters has shortened process times dramatically. Before our avalanche barrel tumbling took two or three days to complete. Today we have shortened times around 60% across the board. Now our planning is centered around how best to leverage this time savings.

For more information; please contact us.  If you are manufacturer; we highly recommend contacting Mass Finishing, Inc. Lastly, we wish to thank Cole Mathison and his team at MFI for their able assistance and for using our project as a case study for their equipment and problem solving abilities.
 

Case Study- G&S Jewelry Manufacturing

G&S Jewelry Mfg is a small woman owned business located in Albuquerque, NM.

Insight on Copyright Law For Jewelry Designers

Copyrighting is an important tool for jewelry designers to protect the product of their imagination and their hands. This protection is available to designers of both large and small companies; even those companies composed of a single person. It is a common misperception that copyrighting is time consuming and very expensive. It can be both of course, but knowledge of the process and requirements will significantly reduce both time and costs.

The copyright extends to handmade designs, handcrafted pieces, investment cast components or any combination that delivers a tangible part. You have spent your creativity, time, sweat and effort to design something unique. YOU own it, protecting it is important. Copyrighting is an excellent means of accomplishing this.

Ryan Wityak has written an excellent summary of the process; it is listed below. Ryan is an attorney at Peacock Myers PC and a part owner of G&S Jewelry Mfg. If you have any questions as to what is covered; he can be reached at:

Peacock Myers PC

Office Phone: (505) 998-6124

rwityak@peacocklaw.com

www.peacocklaw.com

 

Copyright Law Distilled for the Jewelry Designer and Manufacturer

Impact of Oxides in Jewelry Investment Casting

By its nature; investment casting requires predictable filling and flow of molten metal to the extent of the design in the mold. Solidification occurs on the interior surfaces of the mold a progresses inward and upward towards the molten stream source. Ideally any porosity that occurs will be inside or off the piece away  from the surfaces desired for finishing.

To achieve this, it is important that the metal being cast be of uniform composition and consistent in terms of cleanliness and oxygen levels. Dirt or oxide inclusions can inhibit flow of the liquid metal and create two types of defects in the castings. The first being areas where the inclusion will be present on the surface of the piece creating an area that will not polish or breaks out of the surface leaving a hole that needs to be repaired. The second is where the dirt or oxide particle wedges into a via in the mold and prevents metal from flowing down that via to complete the filling. This can be seen in areas where fine detail texture or filigree is interrupted. In these cases the part is likely not repairable and needs to be recast.

The conditions for successful casting require good metal sourcing, care in casting and good process control when recycling scrap. Most casting grain suppliers can meet oxygen demands for sterling investment casting. Use of graphite crucible equipped automatic casting systems with a neutral or slightly reducing cover gas will prevent oxygen from entering the melting stage of the process during casting.

For those casting systems equipped with a window that allows for observation of the melt during melting, the surface of the melt should be clean and lack any white, frosty dross on the surface. Highly reflective surfaces with little or no reaction with the wall of the graphite crucible means that oxygen numbers are low.

A good vacuum seal during the cast process will prevent introduction of oxygen during the flow of metal part of the process. However, when vacuum is broken and the flask is removed from the vacuum chamber, oxygen from the convection cooling in air of the flask will blacken the surface of the tree in whole or in part. Ways to mitigate this include immediate quenching or use of a cover material to scavenge oxygen during cooling prior to quenching.

A good pickle of the tree especially the button will reduce the oxide level of the surface. The sprue and tree scrap can then be regrained in reducing atmosphere to get as much oxygen out of the scrap prior to reuse. Using a melt make-up of 50% max remelt should be successful in keeping oxide levels down to an acceptable level. Higher amounts of virgin metal can be employed as dictated by part design and tribal experience. The skilled staff at G&S Jewelry Mfg is particularly versed with the requirements for successful casting.

 

 

Types of Finishing of Investment Cast Jewelry Components

There are many options for investment cast jewelry components. These include several different types of mass finishing as well as hand finishing techniques. Each have their place depending upon the desired reflectivity, contrast or directionality of the lines of finish texture.

Mass finishing is most commonly employed as it offers low cost, consistency and high quality. It is accomplished in barrels or bowls with wet or dry media. The finish returned can range from a matte finish to a highly specular finish. The level of finish is dictated by the media used, the amount of time of finishing and the stages used for finishing.

Matte finishing can be accomplished using a coarse media dynamically applied enough to remove the rough areas of the casting. This leaves a surfaces that is clean and omnidirectional with no texture lines in the piece. Adding one or two more tumbling steps using finer and harder media will further brighten the surfaces as the peaks and values of the surface become smaller and smaller. Finishing in a ceramic media using a suitable liquid medium to suspend the fine particles will return a highly polished surface.

In the Southwest, many designers want their pieces to have a look that gives the appearance of being worn for many years. In order to achieve this, G&S Jewelry Mfg has developed a technique to deliver a “chaotic” surface with scratches in the surface in random directions. The result is a brand new piece that looks like it has been hard at work for years!

Hand finishing is done on a piece by piece basis. The skill of the buffer along with the media used is critical in achieving the desired look. There are several options here to choose from. Most common is a highly polished surface with bright omnidirectional surfaces on all areas. Alternatives are satin finishes with or without directional texture. A directional texture has a brushed look, all lines of the surface are somewhat parallel. These are most commonly requested for long smooth surfaces such as bracelets.

Hand finishing is more costly due to the labor involved but has it placed depending upon the look desired and customer appetite for the design. G&S Jewelry Mfg is happy to work with its customers to develop the processes that will meet their expectations for color and appearance.

Vacuum Investing for Improved Casting Surfaces

Investing your flasks and using vacuum to draw bubbles out of the slurry is a key component in successful investing. In this scenario, the investment is poured into the flasks and the investing chamber isolated by closing off all openings to the chamber open to atmosphere. A vacuum pump plumbed directly to the investing chamber is then started to create a negative pressure over the top of the open flasks. Observing the surface of the slurry in the flasks, bubbles can readily be seen to rise to the top and pop. The surface will continue to bubble as trapped air is released and the slurry becomes more dense. This means that the slurry will now conform more closely to the surface of the wax pattern inside the flask. The result will be fewer voids and smoother surfaces. The photo below shows an empty flask on a turntable below a tap used to pour investment slurry into the flask. The plexiglass lid seats on a rubber seal on the rim of the stainless steel chamber. When vacuum is applied the lid seals and the inside of the chamber is under vacuum.

Robotech Vacuum Investing System 300x225 Vacuum Investing for Improved Casting Surfaces
Flask on Turntable In Investing Chamber Beneath Plexiglass Chamber Lid For A Robotech Investing System

 

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From Ideation To Creation – G&S Jewelry Mfg Is Your Partner

We have all been there, great ideas but no one there to help you turn your ideas into a product you can hold in your hand. Well, the ownership and talented staff at G&S Jewelry Mfg want to be your partner from ideation to creation. Here is a brief summary of what we can do for you:

Computer Aided Design

Production of a Master

Molding of the Master

Casting of the First Article

Finishing

Painting

Inlay

Solder Assembly

Our staff have decades of experience to ensure that receive the best possible service. We have all of this capability in-house at our Albuquerque, New Mexico facility. Challenge us!

Composite Jewelry Pieces – Adding Colors & Expanding Design Options

Most jewelry is made from one material with perhaps some small additions of solder in assembly. However, we encourage jewelry designers to consider the options of adding color and broadening their options by constructing composite designs.

What do we mean by composite designs? This would be the use of multiple, discrete metals assembled metallurgically, mechanically or loosely together. This could be as simple as stringing different colored beads to soldering a 14 kt charm onto a sterling silver base.

Examples of the colored that can be obtained are: Yellow Gold, White Gold, Rose Gold, Sterling Silver, White Bronze, Yellow Bronze, Copper Bronze and Tan Bronze.

G&S Jewelry Mfg can work with you or your designer to develop new ideas and provide pro forma cost estimates to reach the price point desired. We hope that by offering a color palette and the necessary supporting casting and assembly services, the designer will have more options to choose from when build new designs.

We look forward to working with each and every one of our customers.

 

Valentine’s Day Is Less Than A Month Away!

Yes, Christmas is over but Valentine’s Day is right around the corner! G&S Jewelry can produce one of a kind or mass production of virtually any ring, bracelet or pendant. Challenge us with what you want!

We also have a wide variety of Valentine’s themed items in our catalog. Check our Rings and Bracelets in Our On-Line Catalog.

G&S Jewelry Mfg is a small woman owned business with all of our manufacturing right here in the USA.

Advantages of Tarnish Resistant Sterling Silver for Jewelry Applications

Sterling silver has a long history in use for items of high value. These include coinage, jewelry, hollowware and cutlery. Everyone who has worn sterling silver jewelry knows that it can tarnish rather quickly degrading the look and limiting its appeal. There are many factors that will determine the rate of tarnishing of the surface. If the article is worn against the skin or on leather the tarnishing will be more pronounced than when worn on a wool sweater. In particular, certain skin types, soaps, lotions, perfumes and leather tanning fluids will react with the sterling surface turning the silver color dark.

A solution to this is to substitute a tarnish resistant sterling silver alloy for the standard silver copper binary. The tarnish resistant alloy still meets the hallmark standard for 92.5% minimum silver content, but replaces some of the copper with one or more metals that inhibit tarnishing. These can be exotic materials such as gold, palladium, platinum or more pedestrian elements such as zinc.

The exotic materials will certainly add cost, but the application may warrant inclusion making cost secondary. This would be the case if the sterling piece were to be integrated with a higher value material such as 18 or 14 karat gold where degrading of the sterling piece would detract from the overall beauty of the piece.

Another advantage of the tarnish resistant alloys is the grain refinement and reduction in porosity of the cast part. This translates into a higher quality surface that will polish quicker and smoother.

G&S Jewelry Mfg offers several tarnish resistant sterling alloys and can provide excellent technical support.

 

How CAD Revolutionized Jewelry Design

Innovations in technology have touched every part of modern culture, including art—even art forms as old as jewelry making. The application of computer-aided design (CAD) to jewelry design has completely revolutionized the process, allowing manufacturers like G & S to create unique designs that we can make into precious-metal reality at less cost.

Jewelry Design before CADR17 1 How CAD Revolutionized Jewelry Design

Before CAD, every part of the jewelry design process was Continue reading