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GO to Motor FAQs
 
Manual FAQ Also
see Engineering
Information.
How long will it take to make it?
Adapter plates and brackets and rotary
devices are usually in stock. Linear UniSlides are made to your
exact specifications. Please call Velmex for a precise lead time.
See also our in
stock listing.
Can I buy replacement parts?
Yes, from Velmex.
Do you have OEM or educational discounts?
No, however, we do offer quantity discounts.
What are your positioners made of?
Velmex positioners are made of hard-alloy aluminum
(6000 Series), the slider bearings are thin pads of filled Teflon
material sliding on the aluminum base. Show
Components. The lead screws are either 303 stainless steel or
nickel plated steel depending on pitch. The UniSlide lead screw
drive nut is Delrin or Delrin AF.
All BiSlide and XSlide assemblies bases have
a hard coat finish and are dyed black.
Optionally, the UniSlide base can also be hard
coat anodized or nickel plated. With optional hard coat anodized
finish, corrosion resistance is similar to stainless steel. Lead
screw, nut, and bearing material substitutions are available. See
Engineering
Information.for substitutions.
Can you make it from stainless
steel?
No, they cannot be made from stainless steel.
Our products are precision machined for accuracy. Machining stainless
steel is very difficult because of the hardness of the material.
However, we can anodize or plate the units
so that you have the characteristics of a stainless steel finish
such as surface hardness, abrasion, corrosion or chemical resistance.
And they are lighter in weight. Tell
me more.
What is the smallest Slide you make?
A small unit, with 2.05" length and 0.25
inch travel can be made. The smallest standard Series
A1500 UniSlide has 1.5 inch Travel and is 3.3 inches long, 1.5
inches wide, 0.56 inches high.
What is the longest travel Slide you make?
The longest UniSlide has 88 inches Travel. BiSlides
are available up to 80". For longer travel, see MiniTec
linear system which can traverse 19 feet (5.8 meters.)
Can you re-thread the mounting holes for metric screws?
Yes. Here are the details.
Where can I find a dimensional
drawing for a Series?
At the top of each Series, just below
the title, there is an end view drawing. Click it to see a general
drawing in PDF.
How can I access the mounting
holes in the base of A15 Series UniSlide?
Download this
page for instructions on disassembly.
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of page
Where are UniSlides used?
UniSlides have successfully been used in environments
like, clean rooms, outdoors, underwater, in vacuum,
attached to aircraft, on naval ships, and in outer space. See Motor
Driven Examples or Manual
UniSlide examples
In Instruments and Laboratory Equipment Testing
machines, dimensional quality control testers, compression and tension
testing machines, X-ray and MRI positioning, air and fluid positive
displacement systems, probe and transducer positioning, wind tunnel
testing, air entraining concrete test equipment, plant and animal
tissue measurements, shellfish, and tree
ring non-contact measurements, soil mechanics test apparatus,
ring
engraving machines, ophthalmic instruments, chemical sampling
and handling equipment, microscope and telescope positioning, viscometer
apparatus, counting gnats on figs in Kenya.
Electro-Optics Field
Laser positioning, optical scanning, holographic
imaging, light source and optical element positioning, spectrometer
and spectroscopic equipment, photo transducers testing,
CRT illumination and magnetic field measuring, LCD, LED, VFD, illumination
testing, optical fiber locating, lens and mirror polishing equipment,
video camera positioning, photometer and radiometer positioning,
film imaging alignment equipment, motion picture special effects.
Electronics Production and Testing
Wafer handling, inspection equipment automated
machinery, component pick and place, crystal growing equipment,
antenna positioning, training devices and simulators, cleaving equipment.
Metal, Glass, Rubber, Plastic and Wood Fabrication
Drilling fixtures, engraving machines,
soft material slitting and sawing machines, rubber and plastic dipping,
adhesive disposition, gauging and measurement, punch press backstop
adjustments, welding head positioning, furniture routers, small
parts grinding machinery, packaging machinery, glass and tube machinery,
tire manufacturing machinery.
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Which direction do you call the 'X' axis, the
'Y' axis, or 'Z' axis?
As
a standard we use the machine tool coordinate designations where
'X' is the bottom horizontal axis, 'Y' crosses the 'X' at 90 degrees
and is also in the horizontal plane, and the 'Z' is vertical attached
to the 'Y' axis.
 
Motor FAQ
I want to use my computer to control two axes.
What do I need?
You will need the following items, they come
from Velmex as a complete system ready to plug-in and run: two UniSlide
or BiSlide Assemblies, UniSlide XY Adapter Plate or BiSlide
cleats, two step motors and a Velmex VXM Step
Motor Controller.
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of page
When should I use a step motor?
- For incremental positioning or scanning when
computer controlled motion is desired
- For complex motion requirements of more than
one distances and/or speeds; fast or slow starts/stops, and fast
reversing
- When accurate speeds are required
- For speed range requirements as high as 1
to 8000 steps/sec
- When a brushless motor is required
Will the motor miss/lose steps occasionally?
Step motors, when controlled with Velmex Controllers,
do not miss or lose steps. Step motors run synchronously to their
phase switching speed. When an external motor load exceeds the running
torque of the motor, the motor will stall and totally lose position
much greater than one step. Velmex VXM step motor controllers eliminate
the problems of low speed motor resonance by utilizing half-stepping
and current control. The VXM switches the motor drive amplifiers
directly, eliminating the sensitive pulse to motor translator link.
How do I insure the motor will not stall?
Proper motor sizing and operating the motor in
a range that provides a torque reserve will ensure reliable operation.
Applying the load and increasing motor speed until a stall occurs
will determine the actual marginal torque required. Use the motor
speed/torque curves to determine the maximum reliable operating
speed. We can help you right-size your motor.
If the motor stalls, will it damage the motor?
If the motor stalls, (loses synchronism) motor
output torque drops very low, and the motor current drops slightly.
There are no mechanical parts slipping, only magnetic slippage.
The step motor is a good motor for torque limiting applications.
What is the normal sound the motor should make?
A Step motor makes an audible sound at a frequency
that varies with stepping rate of the motor. Click to play normal
step motor indexing sound.
Normal Motor
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What sound does the motor make when it has stalled?
The motor produces a notably louder sound.
There are four conditions that can cause the motor to stall:
1. The motor is overloaded,
or the mechanism it is driving jams. Click here to play motor overloaded
sound.
Overloaded
Motor
2. The motor is commanded to accelerate at too
high a rate. Click here to play too much acceleration sound.
Excess
Acceleration
3. The motor is commanded to run at very high
speed where the motor produces inadequate torque to operate. Click
here to play motor too fast sound.
Excess
Speed
4. Broken motor cable, or faulty motor amplifier.
If there is only one bad motor connection a lightly loaded motor
may appear to run normally at speeds over 600 steps/sec. At 400
steps/sec. erratic directional changes of the motor shaft will occur.
Click
here to play a normal motor at 400 steps/sec
Click
here to play the motor at 400 steps/sec. with one broken connection
Why don't you offer more servo motors/systems
for your UniSlide assemblies?
Closed loop servo systems have more complexity
and cost without significant benefits when used with Velmex assemblies.
Servo motors have more torque at RPMs over 1000. However, the Velmex
lead screw/drive nut assembly has limited applications at speeds
over 1000 RPM. Mini step/micro step controllers provide smoothness
typical of servos, but at less cost.
Why do step motors work well on UniSlides and not as well on other
devices?
Step motors work better when there is some
frictional load to dampen them. Velmex assemblies have residual friction,
and a polymer lead screw drive nut which absorbs step vibration. Velmex
lead screws have low inertia relative to motor inertia, making very
fast accelerations and decelerations possible. Step motors reach full
torque in just one step.
Variable loads and friction have a negligible
effect on positional accuracy.
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My slide seems to be binding. What could be wrong?
- Your mounting screws in the slider may be
too long and may be hitting the lead screw. (UniSlide only)
- Uneven tension of base mounting screws or
mounting to irregular surfaces will distort the base.
- Lead screw nut or slider gib adjustment over-adjusted
by maintenance personnel.
- Lead screw drive or ways damaged by debris
or overheating.
To measure for binding on step motor driven
systems, check if the lead screw can be turned by hand. Remove any
large load and disconnect the motor controller, grip the screw threads
with both hands, use a rag or gloves to prevent damage to your skin,
you should be able to rotate the screw slightly.
Do I need to lubricate my slide?
Lubrication is most important for motor driven
systems or wherever you want maximum life and the lowest friction.
See the user guide that came with your unit for details.
How do I lubricate the worm drive on the 4800
Series rotary tables?
Normally, the worm/worm gear drive of the 4800
rotary tables does not need any servicing. However, under severe
conditions replenishing the grease will prolong the life of the
gears. Unscrew the red plug that is in the access hole located on
the top surface of the 4800 table. Rotate the table under motor
control until the worm can be seen in the access hole. Squeeze in
a small amount of Lubriplate GR-132 grease and replace the red plug.
How do I lubricate the worm drive on the 5990
rotary table?
Normally the worm/worm gear drive of the 5990
rotary table does not need any servicing. However, under severe
conditions replenishing the grease will increase the life of the
gears. Unscrew the button-head screw located closest to the motor
that attaches the motor plate, squeeze in a small amount of Lubriplate
GR-132 grease into the screw hole and replace the button-head screw.
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