The Linear Motion System.

The Linear Motion System can be defined by the type of bearings utilized.

 

Photo shows  The Thomson Ball Bearing Slides.

Almost every machine designed for Factory Automation, will incorporate some type of Linear Motion System.

There are basically two types of bearings used-rolling-element and plain.

The Rolling-element Bearing.

These bearings consist of an outer ring and several rows of balls retained by cages. Some advantages are-smooth motion, low friction, high rigidity and long life. They are low cost and easy to maintain and replace. Thomson is usually given credit for first producing what is now known as a linear ball bearing. Click here to visit the Thomson Website.

1. Rolling-element bearings must run on hardened steel shafting.
2. They are more rigid than Plain Bearings.
3. They do not handle contamination and should be fitted with
4. They do require some form of lubrication.

Ball Bearing Slides.

Also known as "Ball bearing Drawer Slides" Applications can include-

1. Instrumentation.
2. Robotic Assembly.
3. Cabinetry.
4. Appliances.
5. Furniture.
6. Electronics.

As an example-Accuride International offers a wide range of Drawer Slides-click here to visit their site.

Crossed Roller Slides.

Once considered to be expensive, the crossed roller slide is now very economical and available in a wide range of sizes. I have used this bearings in many applications that would be impossible with other types of bearings. When a wide span is required between bearings, the crossed roller bearing is possibly the only choice. It's tolerance to "stick/slip" is very high.

 

 

The photo at left shows THK linear cross roller bearings and rails. Please click here to visit their website.

 

 

 

Roller slides offer line contact as compared to point contact when using ball bearing slides. Thus greater loads can be tolerated.

Many pick and place modules use crossed roller bearings.

Plain Bearings.

Plain bearings are generally cylindrical in shape and can be straight or flanged. Friction is generally higher than rolling element bearings but cost is lower. I like to consider two types in my automation projects-

1. Bronze bearings.

2. Plastic bearings.

 Photo shows the Bost-Bronze oil impregnated bronze bearings. Please click here to visit the Boston Gear website for further information.

As the name suggests, these bearings are self lubricating and in light load applications can make a perfectly sound linear motion system.

 

 

 

 This photo depicts the   BostonE® plastic sleeve bearing.

With Teflon as their major ingredient, glass-filled bearings are self-lubricating and offer a low coefficient of friction. They withstand extreme temperatures from -400° to +550° F, handle high loads at moderate speeds, and have excellent wear and corrosion resistance. In addition, BostonE® F-1 bearings are machined from extruded rods and held to close tolerances.

 

To visit the Boston Gear website for further information-please click here.

Dovetail Slides.

 The Dovetail slide has been around for a long time. Generally manufactured from cast iron, they can absorb high loads and can be manually operated or powered.

The photo shows the Setco Dovetail slide. Please click here to visit their website, where full details can be found.

 

Rather than designing a slide from scratch, I prefer to purchase a ready made module and Setco offer a wide range of units that can generally be adapted to many applications.

 

Guide Wheel Systems.

We will conclude by mentioning a company that manufactures a very good modular system that is very simple and can have many applications in factory automation. This system is particularly suited for the manufacture of gantry robots and linear motion systems.

The photo here shows the Bishop Wisecarver Dual Vee System. Please click here to visit their web site

 

 

 

 

 

 

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