Introduction to Modular Fixturing


What exactly is modular fixturing? In many ways modular fixturing is just like permanent fixturing, except for a few key differences. First, modular fixtures can be assembled entirely from reusable off-the-shelf components, without machining. Next, many modular components are adjustable and universal. Finally, specially designed tooling plates and blocks, with a standard grid pattern, are the foundation of a good modular system.

A Valuable Tool for Every Machine Shop:
Most metal-machining manufacturers have good applications for temporary fixturing every day! The leadtime and expense required to build a permanent fixture are often difficult to justify. This is especially true when production runs are small and do not repeat on a regular basis. General-purpose workholders such as vises, chucks, and table mounted clamps can be ready for production on short notice, but they are primarily suited for short runs of basic parts. Fortunately, there is now another alternative: modular fixturing. When a company adds modular fixturing to its options, even job-shop-type production can benefit from quality fixturing.

Good Applications for Modular Fixturing:
Modular fixturing is an ideal answer to many workholding problems. One-time jobs, found especially in job shops, are ideal for modular fixturing; with modular fixturing, a workholder can be economically built even for a one-part run. Jobs that do not repeat on a regular basis are well suited to modular fixturing; modular fixturing permits rapid setup of short-notice production runs. Modular fixturing is also ideal for prototype parts; since prototypes are often changed or redesigned, the cost of building a permanent fixture for each new variation would be prohibitive. Replacement parts are another perfect application; modular fixturing allows a company to respond to orders as they are received, instead of shipping parts from an inventory. Trial fixturing is also an excellent application; modular workholders allow a designer to fine tune tooling ideas before a final production workholder is built. Finally, modular fixturing is valuable while permanent fixtures are built or repaired.

The Widest Selection of Tooling Plates & Blocks:
Tooling plates and blocks are the main structural elements of any modular-fixturing system. The type, style, and number of plates and blocks available determine the variety of fixtures that can be built, and also the number of machine tools that can be used. The Carr Lane modular system has the largest selection of tooling plates and blocks available anywhere.

Grid Holes vs. Earlier T-Slot Systems:
The two primary forms of modular systems available today are those with grid-pattern holes and earlier types with T slots to mount components. Grid holes offer many advantages over T slots. Modular systems with grid holes have greater positional accuracy and strength than those with T slots. T-slot systems permit movement along the slot, so nothing but friction holds components in place. Wherever T slots cross each other, a weak point exists.


Multipurpose Grid Holes Offer Maximum Flexibility:
Grid-pattern modular-fixturing systems come in two styles: those with alternating dowel holes and tapped holes and those with multipurpose holes. The alternating-hole style does not offer as many advantages as the Carr Lane multipurpose-hole style. Multipurpose holes have both an alignment bushing and threaded insert in the same hole. This arrangement permits each hole to serve as an alignment hole, mounting hole, or both. Multipurpose holes are laid out in a standard 1" or 2" grid pattern (depending on the size) to allow the maximum number of mounting locations.

Power Workholding Capability:
The ability to use hydraulic power workholding is another consideration in the selection of a modular-workholding system. A modular system should treat power workholding as an integral part of the complete fixturing plan. Instead of requiring special power components, a good modular system uses standard, off-the-shelf power workholding components. Adapting standard power components to modular workholders both reduces cost and expands design options. SWIFTSURE power clamps and work supports are the finest available, and work hand-in-hand with the Carr Lane modular system. Also, our HILMA precision hydraulic vises work perfectly with modular tooling plates and blocks.



Choice of Three System Sizes:
A good modular fixturing system needs to accommodate a wide range of workpiece sizes. Only Carr Lane offers a full line of modular components in three system sizes (Mini, Standard & Heavy). As a comparison to choose the proper system size, the table above shows typical clamping force exerted by clamp straps in each size (2-to-1 lever ratio).