Product category:
Chucks and collets for rotational work
News Release from: Schunk Intec | Subject: Rota NCD 'collet jaw' chuck
Edited by the Manufacturingtalk Editorial
Team on 07 October 2003
'Collet jaw' chucks offer greater
versatility
A 'collet jaw' chuck is more universal than either three-jaw chucks or collets and covers a greater diameter range than conventional collets thus increasing flexibility and cost effectiveness.
The requirement for a machine tool to become ever more flexible is becoming even more critical in today's competitive manufacturing environment With batch sizes diminishing and costs under closer scrutiny the need for ever reducing manufacturing times is critical
This article was originally published on Manufacturingtalk on 10 Mar 2004 at 8.00am (UK)
Related stories
Zero-point clamping system reduces work resetting
Universal zero-point clamping system that provides accurate and repeatable set-ups of workholding fixtures allows workpieces to be moved through multiple operations with minimum resetting.
Universal tool clamping system ups m/c performance
An the alternative to conventional ER collet style toolholders offers ease of handling, more reliable tool clamping, vibration dampening and greater true running accuracy.
Cutting tool technology is continually advancing and reflects savings in the machining cycletimes, but slow change-over times between small batch quantities can crucify the overall floor to floor time of the batch.
Such severe time penalties can easily jeopardise the cost effective and competitive manufacture of small batch quantities.
This situation is exacerbated when the change-over involves a change between the "3 jaw" chuck concept of billet / forging / casting machining to the "collet" machining concept of bar material.
Further reading
Quick chuck jaw change system cuts set-up times
Quick-jaw change system, to be shown at MACH 2006, meets the demands of small batch sizes with exceptional accuracy and repeatability, therefore significantly reducing set up costs.
Magnetic clamping offered for machining jobs
A versatile magnetic clamping system is offered as work holding for rough or fine cutting applications in a variety of machining tasks on milling machines and machining centres.
Four-jaw combination chuck cuts cycle time by 40%
Switching to a four-jaw combination chuck has reduced cycle time in the manufacture of tubular goods for downhole applications by 40% and made set-up easier and safer.
Schunk have addressed this problem with their Rota NCD chuck with patented "collet jaw" capability.
The chuck is a large through bore 3 jaw power chuck based on the "wedge bar" actuation system, providing efficient conversion of the axial forces of the drawtube to high radial forces of the chuck jaw actuation.
The benefits of the "wedge bar" system of the ROTA NCD are :- The teeth on the underside of the base jaws mesh with the teeth of the "wedge bars".
The "wedge bars" are positioned tangientially within the chuck body.
The guideways of the "wedge bars" restrict the outward movement of the base jaws as a result of centrifugal force when the chuck is rotating at speed.
This in turn restricts the typical loss of clamping force of the jaws on the component caused by centrifugal forces.
The result is the ability to clamp thin wallsection components at lower pressures when stationary and maintain sufficient clamping force to retain their clamping at speed, thus eliminating distortion.
Relevant for small bar machining it also enables a higher permissible maximum r.p.m.
to be specified.
In parallel to this the hysteresis effect of the actuation of the jaws when stationary, to the loss of any clamping forces at speed, and the return of the original forces when the chuck is returned to stationary have proven in tests to be negligible.
This has proven to be a significant complement to the design and construction of the Schunk ROTA NCD chuck.
A full range of hard and soft top jaws are available for the chuck, with standard 1/16 inch x 90 degree serration reception, making it universally applicable for billet / forging / casting applications.
To complement the employment of the conventional hard and soft jaws the chuck is capable of accommodating Schunk's standard hard and soft "collet jaws" on chuck diameters 160mm to 315mm diameter via Schunk's patented "collet jaw" system.
This system is achieveable via radial serrations in the bore of the base jaws, such that the "collet jaws" locate via these serrations in the bore of the chuck with the following benefits.
Bar diameters can be accommodated from 6mm with Schunk's standard hard "collet jaws".
Standard hard "collet jaws" cover a specific range of bar diameters, with each jaw set covering a range of between 5mm and 9mm on diameter, depending on chuck size.
The "collet jaw" system is more universal and covers a greater diameter range than conventional collets thus increasing their flexibility and cost effectiveness.
Standard soft "collet jaws" are available to be bored out to suit individual requirements.
They can be through bored for bar machining applications or be bored out to suit individual component diameters and machined with a backstop, for the second operation machining of small diameter components to be conducted with high precision.
The clamping forces are close to the support guideways of the base jaws therefore eliminating the normal tendency for the jaws to "spread".
The radial serrations in the bore of the base jaws are ground such that when meshed with the serrations of the top jaws, the mating angled faces of the serrations create a nominal "pull-back" effect on the top jaw.
This feature further counteract the normal tendancy for the jaws to "spread".
The employment of the "collet jaws" guarantee high precision clamping of small component diameters when machining from bar material, a situation normally only capable with a quality collet chuck The combination of all of these features is a universal three-jaw power chuck that adequately bridges the gap between a universal chuck for billet / forging / casting application and the bar machining capability of a collet chuck.
For the user of a CNC turning centre requiring truly universal workholding equipment the Rota NCD chuck from Schunk is the answer.
It not only eliminates the need for the initial capital purchase of both a three-jaw power chuck and a collet chuck (together with all of the necessary sets of jaws and collets) but also eliminates the physically demanding and time costly exercise of changing between workholding principles. Request a free brochure from Schunk Intec ...
• Schunk Intec: contact details and other news
• Email this article to a colleague
• Register for the free Manufacturingtalk email newsletter
• Manufacturingtalk Home Page
Search the Pro-Talk network of sites
