When constructing a
linear guide system, the first choice is selecting what type of product
to use: a pre-engineered sub-assembly (such as the Uni-Guide) or a
component system (such as Profile Rail Technology [PRT]). Both
have clear advantages and disadvantages; a component system allows the
designer to tailor-fit the system to the application; however a
pre-engineered sub-assembly product can save thousands on
pre-installation costs: time to design, selection, research and
planning. In most cases, the application itself is typically the
determining factor on which system to select. The speed, load, travel
length, precision and environment of the application all play an
integral part when selecting a linear system. Cost is another
important factor to consider. As the number of individual system
components increases, labor installation and alignment costs increase as
well.
In a general industrial application, requiring
a linear guide to move a moderate load (650N/150 lbs) a distance of 1
meter at a moderate speed of 0.5 m/s, a pre-engineered sub-assembly is
the customers’ best balance of performance, reliability and cost. A
simple, easy-to-install, two-piece linear guide system has the advantage
of ease of use. Designing a specifically tailored component system may
seem like the best option; however the cost of design, materials,
installation and alignment are too large to ignore. Take a look at a
full bill of materials list for a component system versus a
pre-engineered sub assembly.
The above costs reflect purchasing the
materials needed. They do not factor in installation and alignment
labor; which is a long and complex process to ensure maximum rigidity,
precision and parallelism. If the two rails are not installed and
aligned properly, the assembled carriage will bind or stall during
travel—leading to low performance, premature life and low
satisfaction for the customer. The simple two-piece rail and carriage
design of the Uni-Guide allows the user to bypass most of these
installation steps, saving the end-user on total installed cost. Listed
below are the recommended installation steps for each linear guide
system:
To summarize, for this type of short
distance/moderate load and speed application, a pre-engineered
sub-assembly is the best choice for the end-user on both cost and
performance; however, linear motion is a broad topic with a wide array
of varying applications. Therefore, different linear motion tools must
be used at different times. To determine which is the solution for the
customer, all of the following criteria MUST be considered: load, speed,
acceleration, travel length, precision, accuracy and environmental
factors.
