Open Access -. The analysis of this work was based on oil has significant effect on the surface finish as compared with kerosene, graphite by weight in oil as a lubricant. A pre-machined surface roughness could be finished and improved surface hardness was obtained. It was found that the response surface model made it possible to visualize overall metal cutting economy and to study optimum conditions of Ball burnishing.

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Bore finishing—The ballizing process. Download PDF. Recommend Documents. A Study of the Ballizing Process. Measurement of half-bore and large-bore features. Bore-hole pumps introduced. The soot particle formation process inside the piston bowl of a small-bore diesel engine. Damaged seal bore repair device.

Membrane expedites well bore measurements. Large bore high field magnets. Medical reports bore me, too. A new bore-hole camera. NEE and V. Traditional hole finishing methods such as grinding and honing are seen to be both time- and energy-consuming when compared to the simpler ballizing process.

Tungsten carbide balls were used with different lubricants to bring about force reduction. Forces were measured using a strain-gauge dynamometer. Surface deformation was studied by means of scanning electron microscopy. A mathematical model is proposed for the prediction of the final diameters of the ballized hole and good agreement is found with experimental observations. Thus, in the industrial employment of the ballizing process, use of the mathematical model will enable a quick determination of the values of the relevant parameters in order for a specified part-diameter to be achieved.

I n t r o d u c t i o n Traditional processes employed in the finishing of bores are becoming more expensive in terms of labour as well as in terms of machine costs. A simple and yet effective process is ballizing, where a precision-ground tungsten carbide or hardened steel ball is forced through a slightly undersized premachined hole.

As the ballizing process both sizes and finishes the bore in a fraction of a second, the production rate is very much higher than that of conventional methods: moreover, only very simple tooling is required. Together with the high productivity, the baUizing process is also a great saver in energy and production cost.

Though the process has been commercialised by the French Enterprise Inc. Gazan and others [] have reported the application of the process but with little in-depth treatment. Recent studies by Yuck et al. Methodology and scope o f investigation Bush-type specimens were used in the study; these have a mean diameter of around The height of the bush is standardised at Interferences from 15 to u m are machined on the internal bore.

The initial surface finish of the bore is varied from 1. The bores were machined with a small-bore carbide-insert boring bar. Prior to each test, the initial conditions of each bush -- i. The ballizing force was recorded by means of a strain-gauge force d y n a m o m eter, see Fig.

Mineral oil and a soapy solution were used as lubricants on a few specimens, while the majority was ballized dry. A mathematical model is proposed to enable the prediction of the final internal and external diameters of the bush.

Strain-gauge dynamometer. Test material and equipment A t Planters hydraulic press was used. Similar to SAE Surface finish measurements were made with Rank Taylor--Hobson Talysurf 4 and roundness with a Rank Taylor--Hobson Talyrond and reference computer 5 unit. The lubricants used were mineral oil, a generalpurpose type similar to those used in gear trains and transmissions, and yellow soap solution, diluted from industrial soaps.

The physical dimensions of the bush were measured by a SIP Mul universal measuring machine with a resolution of 1 micron. In cases where dimensions differed at several places, average values were used. Schematic diagram of the ballizing process. Admittedly there are discrepancies between the ballizing process and the model; the predicted results however, correspond well with the experimental values to an agreement of 10 micron or better, which is acceptable for most applications.

The ballizing process is depicted schematically in Fig. Experimental results and discussions 5. Only specimens with For the same a m o u n t of interference, the ballizing force of EN 43 specimen is m u c h higher, due to the higher yield stress. The effect of increasing the external diameter on the ballizing force is shown in Fig.

The baUizing force increases more significantly when the external diameter is increased from 19 to BaUizing force v8 interference: constant external diameter. If the material is perfectly plastic, then the finished hole will have the same diameter as the ball and if it is perfectly elastic, the finished and initial diameters will be identical, i.

In Fig. Interference of bore before ballizing vs interference after ballizing. In general, at small interferences the points are closer to the perfectly elastic line, indicating that material recovery is substantial.

At larger interference, the final internal diameter is almost constant although the interference changes from to pro. EN 43 has a lower value of final interference -- i. The predicted final interferences using the equations presented in the Appendix are plotted in d o t t e d lines along with the experimental values in Fig. It can be observed that the predicted values are within 2 to 5 pm o f the experimental values at interference greater than pm.

At lower interference, however, the predicted internal diameters are smaller than the experimental values by a margin of 10 to 15 pm. The above observation applies to both brass and EN 43 specimens. It appears, therefore, that the mathematical model is sufficiently accurate for most practical applications. The permanent increase in 20 15 Z v IJ. Effect of lubrication o n the ballizing force. Talyrond traces of the internal diameter before and after ballizing, respectively.

The mathematical model predicts the final external diameter within an accuracy of 20 u m in most cases. Generally the increase in external diameter is much less for bushes of greater wall thickness. Thick mineral oil, however, gives rise to a higher ballizing force when compared to " d r y " ballizing. No apparent causes can be attributed to this observation at present and further investigation -- including the use of EP additive and MoS2 -- is underway.

The MLA after baUizing ranges from 0. Talyrond traces of a typical specimen before and after ballizing are shown in Figs. The perfect circle shown in each trace is the least square circle drawn b y the computer. The improvement in roundness is observed to reach an o p t i m u m value at some intermediate interference value, see Fig.

The o p t i m u m interference is around um for b o t h brass and EN It is believed that at lower interferences, the bore is not well-baUized hence improvement is minimal; at some intermediate interference level, the surface irregularities have been s m o o t h l y levelled giving maximum improvement. This postulation is further supported by SEM micrographs of the ballized surface at various interferences.

Initial Ra values of around 3 to 6 p m are reduced to 0. For brass, the initial Ra of 1 p m is reduced to 0. Surface finish of ballized specimen v s interference. A lightly ballized brass specimen interference around 60 pm is shown in Fig. As the interference is increased to Urn, see Fig. Additional, finer axial markings are observed, which are due to the ball movement: the marks are probably scratched by the metal pick-up of the ball.

At around pm interference, most of the feed marks disappear, see Figs. SEM micrograph of a lightly ballized surface. At this stage, the internal diameter dic equals the ball diameter d b.

Gazan, Better holes by ballizing. Tool Manuf. Gazan, Ballizing - - a high-production tool. Tooling Prod. Aircraft Prod. Robinson, Ballizing, the engineering of holes. Yuek and B. Lee, A study on the bore finishing of cylinders by burnishing.

ICPE, Nee and V. Venkatesh, A study of the ballizing process. Annals CIRP, 30 1 Your name. Close Send.



What is Burnishing Balls or Ballizing? It is a metal-displacement process, in which an oversize ball is pushed through an undersize hole. The ball expands the hole by displacing an amount of material equal to the interference fit. The ball displaces metal by plastic flow leaving a layer of denser metal on the ID wall. In some materials, the ID is work hardened by cold-work ballizing, and wear life of the ID wall increases. Burnishing in manufacturing There are several forms of burnishing processes, the most common are roller burnishing and ball burnishing ballizing. In both cases, a burnishing tool rubs against the workpiece and plastically deforms its surface.


Ballizing process

This application is a continuation of prior U. Provisional Patent Application Ser. The subject matter of the related applications is hereby incorporated by reference in its entirety. This invention relates generally to enlarging or finishing a workpiece bore hole and more specifically to a system and method for ballizing and measuring a workpiece bore hole.


Ballizing or Ball Burnishing with Tungsten Carbide Balls



Bore finishing—The ballizing process


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