ACCU-T: project for reducing boring spindle expansion

JUARISTI is working on a new boring machine with boring bar axial expansion control to combine boring and jig boring large pieces. Boring and jig boring operations in large volume pieces can be done to very low tolerances using the ACCU-T center.

In recent years, JUARISTI has based a key part of its innovation strategy on developing large boring machines for high precision machining of large volume pieces with finishes equivalent to the ones obtained with smaller high precision machines.

Currently, in order to obtain a high degree of precision in machining large pieces, the operators must do a number of manual operations. That means stops must be made while machining to measure the intermediate qualities obtained and do more machining to make rectifications. In addition, the finishes of those pieces ultimately require using a specific type of boring machine called a jig borer, which means a lot of manufacturers need to have two separate machines in their facilities, with the corresponding expense that entails.

To avoid those complications and provide a machine that can do both techniques, JUARISTI is working on developing a new boring machine aimed at large volume pieces that can also do jig boring jobs for finishing pieces.

The development of this new integrated boring and jig boring machine will reduce the environmental impact of machining large pieces. On one hand, it will eliminate the need of moving pieces between the boring and jig boring machines.

And, on the other hand, it will reduce the number of machines manufactured for this kind of job.

With this project, JUARISTI is positioning itself as one of the only suppliers on the market to provide an integral boring solution. Furthermore, thanks to using advanced technologies, it will make that achievement with a level of precision that leads the industry.

The Challenge: Reduce boring spindle expansion

The primary challenge for obtaining high precision with this kind of machine is reducing temperature expansion on the boring bar. The boring spindle is the most important part of the machine. It has a long spindle, up to 2.5 m long, that usually undergoes small temperature variations while machining. Those temperature differences, as slight as they may be, cause a significant expansion in the absolute value (due to the dimensions of the boring bar) that reduce the precision of the machine.

As production becomes more sophisticated and markets become more demanding, companies become less tolerant of those deviations. That requires producers of machine tools to work on new developments that improve the precision of their machines to be competitive in this niche.

Cutting Edge Technologies for Maximum Precision

JUARISTI’s response has been a project for developing a dynamic real time self-calibration system for boring spindle expansion and include it in the new ACCU-T center.

In addition to doing a complete study of the main points of heat in its boring machines, JUARISTI has developed a system based on inductive reading that automatically calibrates the elongation of the boring bar.

Developing this project is a clear opportunity for JUARISTI to reinforce its positioning in the aerospace, wind energy and machine-tool sectors, which are three highly technological industries that have very demanding requirements for finishes of large pieces.

The global budget of the project is 533,255.77 Euros in total. That amount is a significant investment in R&D for JUARISTI. It is an investment that will make it possible to provide key customers in the aerospace, wind energy and machine tool industries with a differentiated product.

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