On Cleaning Parts by the Vibrational Method
Abstract Generated abstract
This paper investigates vibratory cleaning as a safer and potentially more effective alternative to hydro-polishing drums for removing scale from heat-treated twist drills and taps. Experiments on a laboratory vibrating machine tested several fillers, including high-speed steel chips, cast-iron metallic sand, abrasive grains, electrocorundum, and wood shavings, under fixed vibration conditions. The results indicate that high-speed steel chips, especially combined with metallic sand or abrasive media, provide effective cleaning without damaging cutting edges, while subsequent treatment in dry wood shavings removes oil and produces a polished surface. The study recommends limiting drum filling, using filler quantities exceeding the workpieces by two to three times, and identifies production-waste high-speed steel chips as the most rational main cleaning medium tested.
Full Text
ON CLEANING PARTS BY THE VIBRATION METHOD
N. T. Lyapikova
(Presented by the scientific seminar of the Department of Applied and Theoretical Mechanics)
At present, at a number of domestic tool plants, tool blanks are cleaned of scale after heat treatment in hydro-polishing drums with a slurry consisting of a mixture of quartz sand and water.
When spilled emulsion dries, abrasive dust enters the air and the worker’s respiratory organs; therefore this method is not recommended under safety conditions.
Recently, reports have appeared in the domestic and foreign press on the successful introduction of vibratory processing in the field of cleaning and grinding parts. However, the published material is purely advertising in character and does not contain technical details [1—2].
At VNIITmash of the Leningrad Sovnarkhoz, an experimental vibration machine was designed and manufactured, on which experimental research work was carried out on vibration cleaning of cast and stamped parts and tools. But in these works there is not enough information for the rational selection of a filler for one or another type of part. In particular, no data are given on the selection of a cleaning medium for such tools as drills, taps, and others.
In this connection, at the Department of Applied Mechanics of the Tomsk Polytechnic Institute, work was carried out to investigate the vibratory process of cleaning twist drills and taps of various sizes from scale after heat treatment. This work was conducted with the aim of determining the possibility of replacing the cleaning of parts in rotating hydro-polishing drums with the vibration method, and also of identifying the most effective cleaning medium for this specific case.
The processing of parts was carried out on a laboratory installation, the design of which is clear from Fig. 1.
The experiments were conducted under a constant regime, namely: at an oscillation frequency of 2320 osc/min and with an amplitude of vibrational displacement from 1 to 3 mm. The following materials were used as fillers: high-speed-steel chips from under a milling cutter, not washed free of emulsion; metallic sand of annealed cast iron, with a granulation of 0.403 mm; Schliefern (crushed grindstones), grain size 40, GOST 3647—59; electrocorundum 72, grain size 63, GOST 3647—59.
The best results were achieved when using high-speed steel turnings as the cleaning medium in combination with metallic sand made of chilled cast iron, and metal turnings in combination with abrasive shot or electrocorundum.
When workpieces are treated with dry abrasive or electrocorundum in a vibrating drum, a great deal of dust is formed, which must be removed during operation; otherwise the intensity of cleaning drops sharply. If the abrasive is loaded together with oiled turnings, the dust is absorbed by the oil and there is no need for exhaust devices.
Experiments have established that the vibrating drum should not be filled to more than \(3/4\) of its volume. With a small loading volume, col-
Fig. 1. Diagram of a vibrating machine for cleaning parts:
1 — vibrating drum, 2 — unbalances, 3 — flexible coupling, 4 — springs, 5 — drive shaft, 6 — drive-shaft supports, 7 — vibrating-drum supports, 8 — V-belt transmission, 9 — electric motor, 10 — frame, 11 — shock absorber, 12 — base, 13 — loading and unloading hatch, 14 — guard.
lisions occur between the workpieces, which lead to the formation of nicks on the cutting edge of the tool.
The amount of filler must exceed the number of workpieces by a factor of 2–3. Intensive cleaning is observed during the first 15–20 minutes. After treatment for one hour, the workpieces acquire a bright metallic hue. The surface cleanliness obtained is the same as with hydroabrasive cleaning. Subsequent polishing of these workpieces in dry wood shavings gives the surface a glossy sheen.
Table 1
Test results
| Parts cleaned and their weight, kg | Operation | Cleaning or finishing medium | Cyclic frequency, oscillations/min | Amplitude, mm | Processing time, h | Surface quality |
|---|---|---|---|---|---|---|
| Taps and drills Ø 17–19 mm, in an amount of 5 kg | Cleaning | Metallic sand of white cast iron, grain size 0.403 mm, in an amount of 5 kg | 2320 | 32–3 | 1 | No traces of scale or rust; the surface is bright; no nicks are observed on the cutting edge |
| Drills Ø 8–19 mm, in an amount of 4.5 kg | Cleaning | Dry abrasive grain (grinding scrap), grain size 0.40 mm, in an amount of 5 kg | " | " | 1 | The surface is completely cleaned of scale, of a slightly matte shade; on the surface there is a layer of dust from the crushed abrasive |
| Drills Ø 8–19 mm, in an amount of 6 kg | Cleaning | Electrocorundum grain 72, grain size 63, GOST 3647–59, in an amount of 4 kg; emulsol solution in soda water | " | " | 1 | The surface was cleaned to an even metallic shade; no traces of scale; no nicks are observed |
| Drills Ø 28–45 mm, in an amount of 6 kg | Cleaning | Metallic sand of white cast iron, grain size 0.472 mm, and high-speed steel chips from under a milling cutter, in an amount of 12 kg | " | " | 1 | After only 15 min, the surface of the blanks becomes bright; after 1 h the blanks were cleaned uniformly to a bright metallic shade |
| " | Polishing | Dry wood shavings from a planing machine, in an amount of 3/4 of the drum volume | " | " | 30 min | The layer of oil and fine chips was completely removed from the surface of the blanks; the cleanliness of the surface corresponds to that of a polished one |
| Drills Ø 15–50 mm, in an amount of 6 kg | Cleaning | Metallic chips from under a milling cutter and abrasive scrap, grain size 40, according to GOST 3647–59, in an amount of 6.5 kg | 2320 | 2–3 | 1 | The surface was cleaned to a bright metallic luster uniformly. No traces of nicks |
Continuation of Table 1
| 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|
| Drills Ø 15–50 mm, in an amount of 6 kg | Polishing | Dry wood shavings from a planing machine, in an amount equal to 3/4 of the drum volume | ” | ” | 30 min. | The surface corresponds to a polished one. The oil layer has been removed |
| Drills Ø 8–24 mm, in an amount of 6 kg | Cleaning | Metal chips from a milling cutter and wood shavings from a planing machine, in an amount of 9 kg | ” | ” | 2 | The surface was cleaned to a bright metallic shade; there are no traces of oil; the temperature of the mass in the drum rose to 53–60°C |
The duration of the entire treatment is 60–80 minutes.
After rough treatment in high-speed steel chips, the blanks are covered with a layer of oil and crushed chips; during subsequent polishing of these blanks in dry wood shavings, the oil layer is completely removed from the surface of the part.
After finishing, the polished parts need only be wiped with a dry rag or blown off with compressed air in order to remove the light film of wood dust. No additional washing is required, either in water or in an anticorrosion solution.
It has been established that large drill sizes cannot be cleaned in rotating hydro-polishing drums, since during rolling the blanks collide, producing nicks on the cutting edge. In the vibratory drum this danger is absent, since the entire mass, being in a suspended state, rotates smoothly in the direction indicated by the arrow (section A—A).
Drill blanks are cleaned well in a medium of high-speed steel and wood chips. The treatment process in such a medium lasts up to 1.5 hours. The surfaces are bright, without an oil layer (the oil is absorbed by the wood shavings). Further treatment with dry wood shavings gives the surfaces a polished, glossy appearance.
Along with the use of the vibrocleaning method for giving blanks a good commercial appearance and replacing heavy manual labor in polishing the flutes of large-size drills, this method may also be recommended for treating blanks before the welding operation. This will reduce rejects due to lack of fusion at the joint and due to burn marks at the places where the blanks are clamped; in addition, the process of subsequent cleaning of the blanks after heat treatment will be accelerated, since the preliminarily cleaned “raw” blanks will have a smoother surface. The test results are summarized in the table.
Analyzing the results obtained in cleaning tools by the vibration method, it should be noted that the most rational filler of all those tested, in our opinion, is high-speed steel chips from a milling cutter—as the main component of the cleaning medium. High-speed steel chips, being a production waste, require no additional treatment.
References
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I. V. Politov. Vibrational cleaning, grinding, and polishing of parts. Publishing House of the Central Institute of Scientific and Technical Information for Machine Building of the State Committee of the Council of Ministers of the USSR for the Coordination of Scientific Research Work, Moscow, 1962.
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Ya. K. Terent’ev. Vibrational cleaning of metal parts abroad. Publishing House of the Central Institute of Scientific and Technical Information for Machine Building of the State Committee of the Council of Ministers of the USSR for the Coordination of Scientific Research Work, Moscow, 1962.