Welcome to Misumi's new 19-minute Webinar Series.
For those of you here that are new to Misumi,
Misumi is a global supplier of configurable components.
You may ask, why configurable? What is it?
Configurable components solve the designer's dilemma.
A designer has two choices for components; Standard
or Custom. Standard components have a limited selection
and often forced designers to compromise their designs.
These many pluses such as CADs, static part numbers,
fast delivery, often seem inexpensive
and convenient. The other choice is Custom.
Custom components have many drawbacks.
Designers have to make the solid models themselves and all the manufacturing
drawings.
Purchasers too can attest to the long wait for quotes,
the expensive set up charges for short runs, and the long lead times.
We are forced to use Custom components though because of the flexibility.
Misumi offers Configurable,
which is the best of both; easy and flexible.
Configurable components are
easy to design with and purchase. Online, select the product geometry desired,
the material and surface finish, input the size for each configurable dimension
within the range and increments shown.
You'll get a smart part number, price and days to ship,
and the CAD model. All of this configurability
is available with our over one million components
available at misumiusa.com.
Now I'll turn it over to our Misumi engineer.
Hello my name is Mike Malone and I'm an engineer at Misumi USA,
and today we're going to be talking about miniature linear guides.
Let's start things off with a general definition of
what a linear guide is. Miniature linear guides
are a set of components that are used to achieve precise linear motion.
They consist of a block that slides along
a rectangular rail. Misumi obviously sells miniature linear guides.
Our product offering is split into two rail types;
Standard and Wide. It is also split
into to block widths; Standard and Wide,
and in four block lengths; Short,
Standard, Long and Extra Long.
All of our miniature linear guides will fit into one at these categories.
And finally they are split into two basic block types;
Standard, and Interchangeable. Standard type denotes that the block and the rail are
manufactured as a matched set
and as such cannot be sold separately, whereas interchangeable
denotes that the block and rail are not a matched set
and can be sold individually. Linear guides utilize
a recirculating steel ball mechanism that rolls on precisely ground raceways.
This recirculation mechanism allows the block to have a stroke
as long as the rail. The block has to rows of balls,
one on either side of the rail that contact the rail at four points,
two points on each side the track. This design helps to ensure a
consistent ball contact point along the entire rail
resulting in precise motion. The blocks have Ball retainers
that allow the blocks to be removed from the rail
without having the balls fall out. Keep in mind
that while ball retainers are provided, care must be taken when inserting the
rail
into the block as misalignment can bend the
wire retainer, allowing the balls to fall
out. Load ratings are the same in all directions,
meaning that linear guides can be used equally effectively
in any orientation. It may seem counterintuitive
but linear guides work just as well upside down
as they do right side up. The design results in;
high rigidity, allowing the unit to accept moment loads,
long service life and high accuracy, quiet smooth operation,
and outstanding vibration characteristics. Our linear guides are available
in two materials; Carbon Steel and Stainless Steel,
and select linear guides are available with the option of adding
a low-temperature black chrome plating surface treatment.
For those not familiar with low temperature black chrome plating,
it is the surface treatment that is much more durable than a standard chrome
plating.
It is durable enough to be used on bearing surfaces without having to worry
about it flaking
off. It should hold up to about 10 years of use.
As for the accuracy, some of the main tolerances
are listed below. Misumi miniature linear guides are manufactured by the Misumi
Group.
Every manufactured part is inspected.
The assembled rail guides are inspected for friction resistance,
whereas the measured resistance needs to be smaller than recommended values,
and running parallelism, whereas the block reference surface needs to be fully
parallel to the rail surface
over the entire length of the rail. We do have some special grease options
available for our miniature linear guides. Normally,
these guides come with the lithium soap based grease, but there
is an option to change that to a high temperature grease,
or a clean room grease. Note that the heat resistant type,
dust resistant type, and the miniature linear guides with built-in lubrication
units
do not have these special grease options available.
A Datum marks the feature on the part that measurements are taken from.
On Misumi linear guides the datum surfaces
are marked on both the rail and the block. In practice
these marks are used for installation in order to achieve consistency
and accuracy. Continuing with notes on installation,
it is important to pay attention to the flatness of the surface
that is mounted to the block. If this surface is not flat
it can deform the block causing performance and life span
issues. A five micron flatness is recommended.
Also, when installing a rail or a block against a datum surface
it is important that the chamfers in the corner of the mounting surface
are smaller then the chamfer on the rail
or the block. This is to ensure that the datum surface
on the rail comes fully into contact with the mounting datum surfaces.
This may seem like a very small detail but it is important to ensure proper
assembly.
When mounting a rail, linear cam locks can be utilized to ensure
the entire datum surface of the rail comes into contact with the mounting
datum surface.
Both linear cam locks shown above are based upon
eccentricity. As the cam locks rotate in their mounting holes
the head of the cam locks will push against the rail.
Once the seating pressure has been applied
they are locked into place. Not only will these ensure that the rail
is fully seated against the datum surface
but these can also take out slight bends in the rail.
Again, this ensures accurate movement of the block
after assembly. Another way to push the rail
or block against a datum surface is to use locking plates.
Shown are two different types of locking plates.
They both do the same thing, just a little differently.
The plate on the left has two sets of holes;
mounting holes and the set screw hole. Once the plate is firmly mounted,
seating pressure can be generated with the setscrew.
The plates on the right take a more simple approach
in that the plate only has one set holes in it,
the mounting holes. This plate relies on a levering action
generated when the mounting bolts are tightened.
The effect is the same for both. They generate seating pressure,
insuring that the block or the rail is located against the datum.
A third way of doing it is to use Taper Locks.
As the mounting screw is tightened, the tapered edges transfer the vertical
screw tightening force
into a horizontal force. It is important to note
that an additional surface besides the rail or the block
must be provided for the taper lock to push against
during installation. The surface is generally another edge
but could also be something like a set of dowel pins.
So far we have looked at mounting a rail or block
against a datum surface. When a mounting datum surface
is not provided, rails can still be installed.
It just requires a little more work. The important thing to keep in mind
is that both rails must be parallel. To do this,
the first rail installed should be checked against a straight edge
with a dial indicator. Once the first rail is mounted,
the second rail can be installed the same way or can be checked against the
first rail
with the dial indicator. If more space is required between linear guides
and the mounting surface, a set of height adjusting blocks can be used.
So instead of making a set of blocks, you can order these with
all the mounting holes and a datum lip included,
simplifying installation. Once the rails
are installed, some accessories are available that might be useful.
For example, Misumi sells linear guide clamps.
These clamps allow the block to be locked into position.
This lock uses a cam to press against the rail,
thereby locking it into position. A simple method of
providing a hard stop to prevent the blocks from coming off the rail
is to use stopper bolts. These bolts replace the mounting screws
at the ends of the rails. These bolts are long enough that they will physically
prevent the blocks from coming
off the rail. Obviously, these blocks do not have any dampening characteristics.
So if it is expected that the block would come into regular contact with
them,
a dedicated stopper with a softer material on it
like a urethane tipped stopper bolt should be used.
And finally, hole caps can be used to keep debris
out of the mounting holes in the block. They can also be used for aesthetic
purposes.
As for the delivery you can expect, the miniature linear guides with low
temperature black chrome plating
will ship in 11 days . All
other miniature linear guides will ship in six to eight working days.
Note that Misumi does have some miniature linear guides
in stock. When selecting a linear guide for use,
the operating life is most often the primary factor in determining
suitability.
When a linear guide is loaded in linear reciprocating motion,
flaking or scale damage will appear due to material fatigue
as the rolling elements and contact surfaces are constantly
under stress. The total distance traveled
until the first flaking occurs is defined as the operating life
of the linear guide. The rated life is the total distance traveled that 90
percent
of the linear guides of the same type can reach
under the same conditions with no flaking. Where
operating life cannot be calculated, the rated life can be,
taking the following factors into account; basic dynamical load rating,
applied load, hardness factors, temperature factors,
contact factors, and load factors.
While it is beyond the scope of this presentation to get into the actual
calculation of rated life,
we list out here the correction factors,
and this describes how the applied load is calculated.
Note that how the guides are being used, i.e.
their physical layout and orientation greatly affects how the applied load is
calculated.
And finally, this lays out how fluctuating loads
can be averaged to a single load. The following
are a couple of examples of how a linear guide can be used in an application.
In this example, the mechanism uses two sets of linear guides.
The first set allows the main assembly to move
up and down. The second set allows for the smaller subassemblies
to move side to side. Note that when utilizing linear guides
the rails must be supported along its entire length.
This means that linear guides cannot be used to span gaps.
Also note that linear guides should be avoided
in applications requiring very short strokes.
The stroke should be longer than the circumference of the ball bearing used
in the system in order to prevent premature wear
of the bearings. Some of our customers however
have implemented a workaround to this by inserting a long stroke
of the guide after a certain number of short strokes.
The idea behind this is that the long stroke
re-indexes the bearings, thereby preventing the wear from accumulating
on only a selected number bearings. Much like the first example,
this also has two sets of linear guides in it.
The first set allows the subassembly to move
in and out. The second set allows the subassembly
to move up and down. It is also worth noting that,
in general, linear guides can take more moment loads
than a linear shaft and ball bushing. This can result in simplified designs
using a linear guide block instead of a pair of linear ball bushings.
And finally, this slide shows a basically linear stage layout.
The linear guides allow the stage to move back and forth.
In this case, each rail has two blocks on it to provide stability.
Our website is located at
us.misumi-ec.com. There are two main ways to navigate this site.
First, you can search using the search box.
The search box can search for two different things;
either a full part number; for example,
SFJ10-100 will take you to that specific configuration
for that part. The second way
to search in the search box is by description.
For example, you could search for
a miniature linear guide and you can find
your linear guide that way. The second way
to navigate our website is by product groups.
You can simply find your products based on how they're used.
So for example, to find the linear guides,
we look under linear motion and will see that the linear guides
are listed here. Simply select on it
and make the appropriate selections. At this point,
we've come upon a number of selections.
We can narrow down the selection
by making choices on the left-hand side here.
So for example, if we were looking for miniature linear guides,
we can select that here along with the block type
and the rail type. Once you have found the miniature linear guide that you're
looking for,
let's say for example, a Miniature Linear Guide - Interchangeable,
Standard Block, Small Clearance, Standard
L or Configurable Type, you simply click on it.
This will take you to the product description page.
At this point we need to configure this part
to the specific size required.
This is done by making selections on the left hand side of the screen.
So, for example, we can make selections on material,
the rail width, the installed height,
number of blocks, the rail length,
what type grease is required, the type of
length that you're looking for, and as you make these configurations,
the number of part numbers returned--that number will eventually come down to one.
Once that part number is one it'll show the specific part number
for the part configured based on the configuration
at the left. Once all the configuration values
have been selected on the left, the number of part numbers returned
will come down to a single part number.
At this point you can click on the Price Check button
to see how much this particular part costs.
In this case, it's $49.80.
We also see that this would ship in one day.
Keep in mind that the prices listed here
is always going to be a one-piece price.
They do not take into account volume discount rates.
At this point, in order to download the CAD model,
you click on this blue CAD Download/Preview button.
Then all you need to do is click on the 3D Download.
At that point you can select your CAD format
and download your CAD model.
Thank you and we hope you enjoy today's webinar.
All of Misumi's configurable components and one million products are available
at www.misumiusa.com.
If you are new to Misumi, register for access to CAD downloads,
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For first-time companies purchasing you can receive thirty percent off.
Full support is also available:
technical help at engineering@misumiusa.com,
customer service at inquire@misumiusa.com, and your local account manager at sales@misumiusa.com.
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