3D printers for jewelers, as an addition to the router

Many jewelers successfully use in their work program-controlled milling machines, which grind out wax for casting, and some apparatuses - and immediately metal parts. In this article, we will look at 3D printing as an alternative and addition to this process.

Speed

When creating a part in a single copy, the CNC milling cutter wins in speed - the machine milling cutter moves at a speed of up to 2000-5000 mm / min and, where the milling cutter can handle in 15 minutes, the printer can print the part up to one and a half hours, sometimes even more.
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This is true, however, only for simple and smooth products, such as a wedding ring of a simple shape and without a pattern, which do not require high surface quality, since they are easy to polish quickly. The frezer grinds complex products as slowly as a 3D printer prints them, and often even longer - the processing time can take up to six hours.


Photo @ FormlabsJp

When you create a series of products right away, the situation changes dramatically - in one pass the printer is able to print out a full waxing platform - this is a platform (for example, a Form 2 printer) 145x145 mm, and they are placed there, depending on the size of the models, up to 35 pieces. With a printing speed of 10-30 mm / hour (and it prints in layers, over the entire area of ​​the platform), this gives a noticeable advantage over the router, which cuts only one model at a time - this is either one complex piece, or several simple, flat ones, from one cylindrical wax billet.

In addition, the 3D printer can print the Christmas tree of models for casting at once, without the need to assemble it from separate blanks. It also saves time.


Photo @ 3d_cast

Accuracy and quality

The accuracy of the positioning of the cutter in the CNC machines reaches 0.001 mm, which is higher than that of the 3D printer. The quality of surface treatment with a router also depends on the size of the cutter itself, and the radius of the cutter tip is not less than 0.05 mm, but the cutter’s movement is programmed, usually a third or half cutter step, respectively - all transitions are smoothed.


Photo @ freemanwax

The thickness of the layer when printing on Form 2, the most popular but far from the most accurate printer, and hence the vertical accuracy, is 0.025 mm, which is two times smaller than the diameter of the tip of any cutter. The diameter of its beam is 0.14 mm, which reduces the resolution, but also allows you to get a smoother surface.


Photo @ landofnaud

In general, the quality of the products obtained on a photopolymer printer and top milling machines is comparable. In some cases, on simple forms, the quality of the milled part will be higher. With the complexity of the forms, the story is different - a 3D printer is able to print such that no mill will ever cut out, due to design limitations.

Efficiency

Photopolymers that print stereolithographic printers are more expensive than ordinary jewelry wax. Large pieces of wax after a milling cutter can be melted into new blanks, although this is also time and unnecessary actions, but also savings. Milled wax is cheaper, in terms of the cost of each single product of a similar volume.

Wax is not the only consumable material in the work of the router, the milling cutters also gradually grind and require replacement, they last for 1-2 months of intensive work, but this does not greatly reduce the gap.

Work frezer, in terms of cost of manufactured products, is cheaper.


Photo @ 3DHub.gr

Convenience and features

The specificity of milling is such that even on a five-axis machine, the milling cutter is not able to reach anywhere. This forces jewelers to create composite models of several parts, which then need to be soldered, or even pre-finished manually. A 3D printer, however, is able to print a model of an arbitrarily complex shape, including internal cavities and complex joints, in one pass.

How does this happen

Printed models are soldered to the wax barrel, then the resulting structure is filled with plaster or a special solution, after hardening of which the finished form is heated in a furnace, and then filled with metal.

The wax-free material burns out, allowing the metal to take up all the vacant space and exactly repeat the shape of the blank.

More details:

1. The casting process begins with the printing of the model and the standard post-printing processing - the printed part is separated from the supports, washed, subjected to fixing exposure in the ultraviolet, and if necessary, slightly polished.



2. Further, the process is similar to that used in casting using conventional waxes. The blanks are soldered to the wax sprue, which will keep them in the correct position and create a channel for the distribution of the metal.


If the number and size of products allow, you can skip this step - if you print out the products together with the sprue as a whole.

3. The sprue is fixed in the casting flask. If the flask is perforated, the holes should be closed, for example - with packing tape.


4. The filling solution is mixed in the proportions specified by the manufacturer.


Then it is poured into a flask with a sprue inside. Pour gently, so as not to damage the model and not to dislodge the Christmas tree.


5. The flask is placed in the vacuum chamber for at least 90 seconds so that all the air comes out of the solution. Then it is transferred to the place protected from vibration, for the fastest hardening.


6. Injection tanks are placed in an oven, cold or heated to 167ºC, and gradually raise the temperature until the models are completely burned out.



Preheat - preheat.
Insert flask - place the flask in the oven.
Ramp - raise (change) the temperature.
Hold - hold temperature (example: 3h = 3 hours)

7. Upon completion of this process, metal is poured into the mold.

8. After pouring, the mold is cooled, the filling material is washed out.


9. It remains only to remove the finished products, separate them and lightly polish.

Photos of products created by Top3DShop :

Findings:

Both technologies have their pros and cons. If the jewelry workshop already has a CNC milling machine, then it will cope with most of the tasks for making single copies. Moreover - if only single copies are made and not very often, then the machine here and in speed wins.

If the task is not to develop production, increase the scope of work, turnover of funds, raise the level of complexity of products, then the 3D printer will be only an additional financial burden.

With an increase in the pace and volume of work, with the constant introduction of new models, the advantages of a 3D printer will be noticeable immediately; in serial production, the difference in speed is serious. The printer is difficult to overestimate the rapid prototyping and production of batches of blanks.

If the enterprise fulfills both types of orders, both single and serial, it will be more efficient and economical to have both devices on the farm, for different types of work, they will organically complement each other.

Equipment

Formlabs Form 2

Technology: SLA
Working chamber: 145 x 145 x 175 mm
Layer thickness: 25-100 microns
Laser focus: 140 microns
Beam power: 250 mW
Price: 320,000 rubles

Form 2 is a compact stereo lithographic 3D printer that fits easily on a desktop.


Due to its accuracy (25-100 microns), it is very popular among orthodontists and jewelers, as it can print many products in one session.


Photo @ FormlabsJp



Photopolymer for printing burnable models costs 46,000 rubles for a 1 liter cartridge.

3D Systems Projet MJP 2500

Technology: MJM
Working chamber: 295 x 211 x 142 mm
Resolution: 800 x 900 x 790 dpi
Layer thickness: 32 microns
Price: 3 030 000 rubles

The multi-jet printer of 3D Systems, designed for printing castings with VisiJet materials and functional parts with plastics.


MJP is inferior to stereolithographic printers in compactness - it is much larger and can not be placed on the desktop, but this is offset by the speed of printing and a larger work area.

3D Systems ProJet MJP 3600W Max

Technology: MJM
Working chamber: 298 x 183 x 203 mm
Resolution: up to 750 x 750 x 1600 DPI
Layer thickness from: from 16 microns
Printing accuracy: 10-50 microns
Price: 7 109 000 rubles

ProJet 3600W Max is an improved version of the ProJet 3500 CPX model, a specialized 3D printer for printing injection waxes. These are industrial 3D printers used in production in a continuous operation mode, with a large platform and high performance. The printers of this series use Multi-Jet Modeling (MJM) technology, which increases the speed of work and allows the use of specially designed materials for it VisiJet.


The M3 Cast wax used in it is highly durable; models from it do not break in the hands when detached from the platform or accidentally dropped, as happened with models printed from its predecessor, Hi Cast.

It is worth the material 95 263 rubles for 1.7 kg

Flashforge Hunter - 3D Printer

Technology: DLP (digital light processing)
Printing area: 120 × 67.5 × 150 mm
Layer thickness: 25-50 microns (0.025 / 0.05 mm)
Resolution: 62.5 microns (0.0625 mm)
Price: from 275,000 rubles

Hunter is a new Flashforge DLP 3D printer. DLP - stereolithography technology using a projector instead of a laser.

This technology has its advantages - DLP-printing is faster and can provide greater detail on ultra-small scales. On the other hand, the DLP projection consists of pixels, if a smoother surface is needed - it is better to choose an SLA printer, for example, Form 2.


Flashforge Hunter DLP 3D is compatible with the third generation of stereolithographic resins, which gives the user a wide choice of materials for printing.


The printer uses a self-developed DLP module from the manufacturer, the characteristics of which are optimized for 3D printing. This component has a higher linear accuracy than conventional DLP designed for home video projectors.

Wanhao Duplicator 7 v1.4

Printing technology: DLP, 405nm
Maximum printing speed: 30 mm / hour
Maximum print area: 120x68x200 mm
Resolution: 2560x1440 pixels per layer
Accuracy: 0.04 mm
Layer thickness: 0.035-0.5mm
Weight: 12 kg
Price: 35 900 rubles,
version 1.3 is also available for 24,900 p., the difference between them can be found at the link .

Wanhao Duplicator 7 is an inexpensive photopolymer printer for trying stereolithography. The disadvantages of this model are low stability, low resolution and problems with repeatability “out of the box”.


Photo @ Sarah IE Monstah

Each copy requires time and attention of the owner, careful adjustment, sometimes flashing to get a distinct result.


Photo @ Simone Rasetti

Although, someone and the first time turns out well.


Photo @ Jin Shina

Wanhao has not yet presented their own resins for printing burnable models, but with this printer you can use any UV curable photopolymer with a wavelength of 405 nm, which is a standard feature for them. For example, MadeSolid Firecast or PhotoCentric Castable .

For work, he is unlikely to suit anyone. But for experimentation and experience, this is the best choice given the price.

A scanner is needed in cases where you need to create a digital copy of an existing product, whether for subsequent replication, or its modification and the manufacture of a new product.

Range Vision - Spectrum - 3D Scanner

Resolution: 0.072 mm
Camera resolution: 3.1 MP
Scanner Technology: Optical
Accuracy: up to 0.04 mm
Price: 295 000 rubles

RangeVision Spectrum has 3 scanning areas and color cameras with a resolution of 3.1 megapixels. Available with a rotary table and carrying case. The device is designed and manufactured in Russia - it is possible to order additional accessories in a short time.

Any product printed from photopolymer resin requires an additional exposure - backlight. This can be done in bright sunlight, and any UV lamps, but for the stability of the result, it is better to use a polymerizer.

XYZprinting - Curing Chamber - Polymerizer

Emission range: 385 nm
Power: 16 W
Loading objects: up to 1.5 kg
Exposure: 1-60 min
Diode service life: 10,000 hours
Working volume: 180 mm diagonal, 200 tall
Weight: 4 kg
Price: 24 900 rubles

XYZPrinting polymerization chamber is used for final processing of products printed by stereolithographic printer. The device is simple to operate: it is enough to place the products in the chamber, set the time and intensity of irradiation and wait a few minutes.


The ultraviolet diodes of the camera have a working life of 10,000 hours, so it will become a useful and durable tool. The product is exposed to radiation evenly, from all sides, thanks to the internal mirror wall automatically rotating by 360 degrees, which allows reducing the exposure time and improving the quality of processing.

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