Self-aligning bearings speed machine assembly

Edited by the Engineeringtalk editorial team Jul 20, 2004

A new generation of machines for producing air pillows, used to fill voids in packaging cartons and cases, uses easy-mounting self-aligning bearings to reduce build time and costs.

A new generation of machines for producing air pillows, used to fill voids in packaging cartons and cases, uses easy-mounting self-aligning bearings from Unimatic Engineers to reduce build time and costs without sacrificing accuracy and reliability.

Coventry-based Amasec Airfil has been at the cutting edge of filling technology since its founding 10 years ago.

Last year while on a proactive trade mission to America, Director Dave Watkins identified a new potential market niche for small, low cost machines.

"I realised that vast numbers of smaller companies could not afford machines, and so were packing by hand", he says.

"This is time-consuming, messy, wasteful of the filling material and they often used environmentally unfriendly expanded foam beads".

"I began to formulate design ideas and got a commitment of support from a major US business that is structured as a large chain of small depots".

Air pillows are formed from a plastic film sleeve that is sealed at one end, inflated and then sealed at the other end.

Watkins' concept was based around motorising a simple hand seal.

A feed mechanism indexes the sleeve through heated sealing jaws and a blower inflates the sleeve.

A second seal is then made thus creating the pillow and the next length of sleeve is indexed into position.

This motion is created through a clutch mounted in one of the several wheels that guide the film through the machine.

The wheels are all mounted on Unimatic self-aligning bearings.

According to Watkins the Unimatic bearings are a key part of the whole concept.

"It is critical to this project that we keep our build costs to a minimum, and the self-clinching bearings can be fitted in seconds as they are just knocked into position".

"With conventional bearings there is considerable time and effort expended marking up the mounting position to painstaking accuracy, then forming the hole and positioning the bearing to a fine tolerance".

"When you are producing machines serially, each having a good number of bearings, that adds up to a significant cost".

Design engineers in all industries often find that it costs more in time, money and effort to install and support a bearing than it does to buy the bearing itself, particularly if the bearing is fitted into sheet material.

The Unimatic bearings overcome this by effectively being built into a housing, the external design of which provides a self-clinching effect for mounting.

Internally the housing holds the bearing with up to +/-5 degrees of inclination to compensate for misalignment so that dimensional tolerance of the mounting hole is not critical.

An additional benefit of this concept is that the bearing is clean, it being virtually impossible for lubricant to leak out onto the sleeve.

Since Amasec introduced the new Airfil Zephyr 250 late last year, the entire company has been transformed, with unit production values increased by an order of magnitude.

"The demand is tremendous", says Watkins.

"Fortunately, with the low build time we have been able to ramp up production to match".

"But the biggest change is that users are now looking upon us as great innovators and coming to us with either problems to be solved or half-formed ideas for new developments".

"We have increased our R and D effort no end and are currently exploring several new avenues including a faster machine, a programmable machine with which you will be able to make pillows of all shapes and sizes, and a machine that uses plain sheet film instead of a preformed sleeve".