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What is tumbling of jewelry. Four types of tumbling. Comparison of tumbling processes. A very long time ago, people noticed this process in nature, when they watched a river or sea, the waves of which caressed the stones located on the coast, and, thereby, formed

Jewelers, car enthusiasts, and manufacturers of facing materials often face the same question: how to make a beautiful, shiny surface for a product? Tumbling comes to the rescue. a technological process in which the hard surface of a part is cleaned and machined.

The essence of the method

Tumbling involves mixing the parts being processed in a container. The interaction of components occurs in two ways of movement:

  • rotary (rotating);
  • vibrational.

Solid tumbling bodies, due to friction, clean the surface to the desired level of gloss or roughness by removing microparticles from it. The process can take from 4 to 80 hours.

The advantage of this method is the ability to process surfaces with non-standard shapes and sizes. Disadvantages include the inability to process thin-walled parts.

It is worth noting that tumbling is a process of rolling in parts that can be done using two methods:

  • dry;
  • wet.

The dry method uses special pastes, powders and abrasive components. With the wet method, working fluid, coagulants, and tumbling solutions are added to the drum. Wet tumbling is used, as a rule, before applying various types of coatings: galvanic, enameled, and so on.

Where is it used?

Answering the question of what tumbling is, it should be noted that in addition to polishing, it allows you to remove flash, burrs, rust, and scale from parts. Selecting the right abrasive material will give the desired roughness and specularity to the surface. Areas of application:

  • instrument making;
  • mechanical engineering;
  • construction;
  • jewelry making.

In addition, tumbling is used for household products (knives, blades, blades), car rims, natural materials (stones), and plastic products.

Tumbling of minerals is done to give stones a beautiful appearance, shine, grind off sharp edges, create smooth lines, and get rid of plaque and chips. Such products can later be cut or used as talismans and amulets. Tumbling is performed for such stones as:

  • citrine;
  • aquamarine;
  • amethyst;
  • shungite;
  • jasper;
  • quartz;
  • obsidian;
  • malachite;
  • agate;
  • cornelian;
  • rhinestone;
  • hematite;
  • aventurine.

Equipment

For tumbling, special tumbling machines are used, which are standardized by GOST 10548-74. The working surface in cross section is a circle or a prism.


Tumbling materials

We can say that tumbling is such collisions, sliding and micro-cutting of the surfaces of parts with an abrasive filler, in which the final result will depend on the type and material of the lapping bodies. The following are used as cleaning tools:

  • sea ​​pebbles;
  • abrasive grain;
  • granular abrasive;
  • corn macerate;
  • nut shell;
  • polished steel spheres;
  • ceramic and vulcanite abrasives;
  • quartz sand;
  • limestone;
  • wooden bodies.

Step-by-step tumbling is often used, when the size of abrasive particles gradually decreases. The shape of the lapping bodies can also be different:

  • tetrahedron;
  • parallelepiped;
  • cylinder;
  • cone;
  • prism.

Sometimes it can take more time and resources to finish the processing than it does to manufacture the part.

Metal tumbling is one of the methods of processing metal products and involves cleaning surfaces from dirt, corrosion and scale. The final result is similar to the effect of polishing. The technology of tumbling is that abrasive material is loaded into the equipment container, along with the workpiece that needs to be processed. In some cases, in order to improve the quality of processing, water and a compound (thermoplastic polymer resin) are also added to the container. The use of various chemical compositions makes it possible to process a wide range of materials.

Types of tumbling

There are several types of tumbling:
- rotary (the interaction of abrasive elements and the material being processed in a rotating drum. The productivity and speed of processing with this method are not very high, but the quality of metal processing is quite good);
- vibration (compared to the rotary method, the processing is higher quality and faster, it is also possible to process elements of any size and configuration);
- dry (using conventional abrasive filler);
- wet (water is added to the equipment container, which promotes better cleaning and allows you to polish the surface).

Types of equipment

Equipment for tumbling is divided into: - drum tumbling - when the drum with filler and parts rotates, towing tumbling occurs, and the tumbling elements polish the stationary product; - vibration - in such a unit there is a chaotic movement of parts and tumbling bodies in the drum due to vibration created by the engine; - electromagnetic – in which the filler moves due to the magnetic field created by the rotor. This processing method allows you to polish parts even in hard-to-reach places.

Fillers

Tumbling fillers are the basis for finishing the surfaces of various products. Modern fillers for tumbling are durable and efficient, and have different abrasiveness, sizes and geometric shapes. When choosing a filler, factors such as:
- the shape of the abrasive body (for smoothing surfaces, for example, conical abrasives are used, and for rounding edges, a prism shape is used);
- required abrasive properties;
- size of the material (depending on the degree of processing);
- type of material (abrasives made of wood, plastic, porcelain, glass, etc. can be used).

Before reaching the store window, jewelry must go through many stages of production. Today we will tell you about where products end up after the foundry.

Grinding

Jewelry cast in metal can hardly be called flawless. It is for this purpose that they go to the polishing area, where the skillful hands of jewelers bring the product one step closer to perfection.

Grinding is necessary in order to give the metal surface a certain purity and precise dimensions. So, the craftsmen level the place of the cut sprue, which was used to attach the product to the wax rod of the tree, or remove the flash - that is, excess metal that could have formed during the casting process.


For this, a special machine with a grinding wheel consisting of small carborundum crystals is used. The grinder brings the product to the wheel, “removing” excess metal. To work out the smallest details, a hand tool is used - a drill with many attachments that differ in size and hardness, or a file.

Only after manual grinding does the product pass to the tumbling section.




This jewelry production area resembles a huge kitchen, where in each “pot” something is prepared under the strict guidance of an experienced chef. True, instead of “kitchen utensils” in tumbling there are huge rotating drums, and jewelers play the role of chef.

Tumbling is actually a jewelry cleaning process that combines grinding and polishing. Products are placed in rotating drums with special polishing agents or reagents. Typically, tumbling involves two steps: wet grinding and dry polishing - but for some products only dry finishing is sufficient.


First, the decorations are placed in a rotating drum, into which a buffer solution with reagents is poured. The reagents can be detergents and polishes, as well as a solution of caustic soda, slaked lime, soda ash and some other substances that speed up the cleaning process. At the same time, special small steel balls are placed in the drum.

After a certain time, the contents of the drums are poured into a container that looks like a huge sieve. Everything that is not needed goes away, but the cleaned jewelry remains.


The second stage is dry polishing. The principle of tumbling is the same, only instead of solutions, dry abrasives are poured into the drums: ceramics, porcelain, plastic, corundum and even walnut shells, which, according to tumbling jewelers, cannot be compared with any synthetic material. The buried figures have the shape of a pyramid, cone, cylinder or ball.




Specialists not only load and remove products, but also monitor the time: it is important to correctly set the operating parameters of the equipment and not damage the metal and design elements of the jewelry.

Polishing

To “brine the shine” the product is sent to polishers.

Using a polishing machine or manually using a drill with special attachments, jewelers make jewelry incredibly smooth and shiny.


Unlike sanding, polishing does not use harsh abrasives, but only smooth or soft materials such as felt, felt or wool. Before starting work, the product must be degreased. To reduce friction and remove possible fine chips, so-called polishing water (soap solution with ammonia) is used.



First, the product is processed from the inside (if necessary), and then from the outside. The polisher, as it were, draws strokes on the surface of the metal, first in one direction, and then “across” so that there are no stripes.

Only after this does the jewelry acquire a shine worthy of the precious metal. It must be said that some products are polished not only at this stage of production, but also later, after the stones are set.


Tumbling is a method of finishing products in the environment of loose abrasive bodies. Abrasive bodies may be called tumbling filler or tumbling abrasive.
Depending on the method of mixing the tumbling filler in the drum of a tumbling machine, we can talk about several types of tumbling. Let's look at the different types of tumbling machines, their advantages and disadvantages.

1. Tumbling drums.

The simplest type of tumbling equipment. The machine is a cylindrical or multifaceted drum. The drum can be positioned horizontally, vertically, or inclined relative to the axis of rotation and is driven by an electric motor. Tumbling processing is carried out due to the free mixing of products and tumbling bodies while the drum rotates.

The undoubted advantages of this type of tumbling equipment include low cost and simplicity. At the same time, a large number of disadvantages inherent in drum tumbling lead to the gradual displacement of this type of processing by other more advanced tumbling methods.

Disadvantages of drum tumbling machines:
  1. Low processing speed compared to vibrating machines and rotary finishing machines.
  2. Problem with separation (separation) of products and tumbling bodies after completion of processing.
  3. Difficulty in implementing wet processing.
  4. Impossibility of delicate processing of products of complex configuration, thin-walled and easily deformable products.
  5. Impossibility of visual control of the tumbling process.
  6. Uneven surface treatment in products with complex configurations.
  7. High noise during drum tumbling operation and the need for additional noise insulation or removal of tumbling equipment to separate rooms.

All of the above has resulted in the fact that drum tumbling today is used, as a rule, only for simple tumbling processes that are undemanding in terms of surface quality. For example, eliminating traces of casting (burst, sprues, etc.) after foundry processes.

The most popular type of tumbling equipment today. It is a working area in the form of a drum (bath, tube, etc.) with an attached vibration drive. Parts and finishing bodies are mixed into the work area. Very often, solutions of compounds are additionally added to the work area (wet or physical-chemical type of tumbling treatment).
The operating principle of the vibrating tumbling machine is as follows. Using an electric motor with a vibration drive, the working area of ​​the machine (with tumbling filler and parts loaded into it) produces oscillatory movements. These vibrations cause the products and filler to move relative to each other. As a result, the abrasive tumbling bodies begin to cause microimpacts on the surface of the products, which leads to micro-removal of material from the surface of the product.

Currently, a huge number of vibratory tumbling machines of various sizes and designs are produced. For example, to speed up the tumbling process, products can be rigidly mounted on a spindle and during vibration processing, additional rotational movements are imparted to these products.

Advantages of vibrating tumbling machines.
  1. Versatility. When changing the range of processed products, as a rule, it is enough to change the tumbling bodies to ones more suitable for new products.
  2. Possibility of simultaneous processing of large batches of products by loading in bulk.
  3. High processing speed compared to drum tumbling machines.
  4. Possibility of processing thin-walled products.
  5. Possibility of uniform finishing of products with complex configurations.
  6. Possibility of delicate tumbling processing of products made of soft materials.
  7. Possibility of visual control of the processing process.

A specific type of tumbling equipment that has recently become increasingly widespread. The operating principle of rotary (or centrifugal) finishing machines is as follows. The working chamber is a stationary, vertically mounted drum. At the bottom of the drum there is a rotating plate with blades (the so-called actuator). Products and tumbling abrasives are loaded into the working chamber in bulk. After putting the actuator into rotational motion, it imparts rotation to the entire mixture of tumbling bodies and products.
Moreover, to increase the processing efficiency, the inner surface of the stationary working area has a special profile, which sets the planetary-torus-shaped trajectory of the tumbling mixture.
The main disadvantages of rotary machines include the inability to process heavy and bulky parts, as well as a high level of wear on the inner surface of the drum and the interface between the drum and the actuator (especially during wet processing).

Advantages of rotary machines.
  1. The highest productivity among tumbling machines in a free abrasive environment.
  2. Possibility of simultaneous processing of a large number of parts.
  3. The ability to set the final surface roughness of products by adjusting the actuator rotation speed. The principle is “lower frequency, cleaner surface.”
  4. High quality of the resulting surface (achievable parameter Ra 0.30-0.35)

4. “Towing” finishing (spindle finishing, drag finishing).

A specific and rarely used type of tumbling equipment, characterized by very high processing efficiency.
Operating principle: the workpiece (or several products) is attached to the spindle. Next, the spindle is given a rotational movement and it, together with the part, is lowered into the working bowl with tumbling abrasive. In the contact zone between the surface of the product and the abrasive, material is quickly removed from the surface of the workpiece. To update the abrasive in the contact zone, either the spindle is given slow additional movements (left-right, up-down relative to the bowl with tumbling bodies), or a vibrating drive is connected to the working bowl (by analogy with vibrating tumbling machines).
The main disadvantage of towing tumbling is the simultaneous processing of a small number of products.

At the same time, towing tumbling allows you to obtain a very high quality of surface treatment with minimal processing time. This has led to the fact that towed finishing machines have become widespread in high-tech industries (aircraft construction, precision mechanics, medical prosthetics, tool production, etc.) industries where the requirements for the surface quality of products are very high.

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Galtovka

the process of cleaning the surface of small workpieces and parts from burrs, scale, molding soil, corrosion, etc. It also serves to improve the quality of the surface of products - polishing (See Polishing). G. is carried out in drums. To speed up the grinding, abrasive materials—sand, emery, corundum, etc.—are loaded into the drum along with the parts (dry grinding), and sometimes various solvents are poured in (wet grinding). For polishing, wooden sawdust, leather scraps, etc. are loaded into the drums along with the parts (dry polishing), and sometimes solutions of soap, alkali, etc. are introduced (wet polishing). For better mixing, drums with eccentric rotation are used.

During vibrating tumbling, the working chambers are subjected to vibrations in several directions with a frequency of 15 to 50 Hz, which ensures complex movement of parts and abrasive particles. The vibrating tumbling machine allows you to process large parts (in a fixed form).

Hydrotumbling is also used, which creates a surface hardening that increases the fatigue strength of the part material. When hydroplating, parts are fixed in a chamber inside which moves liquid with fine metal shot.

D. I. Braslavsky, V. M. Raskatov.


Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

Synonyms:

See what “Galtovka” is in other dictionaries:

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