Frequently Asked Questions

PBC Linear does not offer end stops for any Round Shaft Technology.

Standard Simplicity bearings with the Frelon liner and anodized aluminum housing are not considered FDA “approved.” However, they are FDA compliant when installed properly. If the food item is not yet packaged, Simplicity bearings are compliant as long as there is no contact with the food item. If the bearings are located over the unpackaged food item, there should be some sort of shield between the bearings and the food. If the bearings are located away to the side or below the unpackaged food, no shielding is necessary. If the food item is already packaged, there is no issue. The Frelon W liner is suitable for food contact.

Simplicity Frelon lined bearings are designed to run on shafting with a surface finish of 8-12 RMS for best performance, but can accept up to 16 RMS. Rougher shafting can be used, but both bearing and shafting will wear at accelerated rates and binding may occur. Likewise, shafting that is smoother than 8 RMS will result in accelerated wear because the Frelon will not be able to accomplish the transfer process.

Simplicity linear plain bearings are made to industry standards and can offer a dimensional interchange to most other manufacturers’ linear bearings. This comparison applies primarily to ID, OD, and length. Differences such as distance between snap ring grooves, materials, or load ratings should be addressed according to the customer's specific application. It is the customer's responsibility to verify proper fit for their application.

The thickness has been optimized to provide long life for almost all applications.  The exact thickness is confidential.

For an off-the-shelf item, the SDS, DDS, and PAC die sets offer options for a flange mount in diameters up to 2".

PBC does not offer a brake for the Simplicity pillow blocks.

You may use removable thread locker to hold the adjustable bearing plugs in position on the square bearing.

Seals are installed into grooves machined into the ID of the bearing, therefore the overall length of the bearing is not affected.

PBC Linear recommends use of the compensated ID bearings for press fit applications. Inch (PS & PSF) and metric (PSM & PSFM) sleeve bearings have fit info in the dimensional tables specific to each particular series in the Round Shaft Technology catalog.

For a Simplicity Plain Bearing product the velocity and acceleration is rated in terms of speed or “PV” this is a calculated value based on “P”resure (or load) multiplied by “V”elocity (speed) to determine the acceptable speed of the bearing in a given application.

Please see our Round Shaft Technology catalog for specific technical specifications.

In general terms, if the load or driving force is located (1) off centerline of the bearing(s), or (2) in the line of movement but some distance from the bearings, this distance must not be greater than twice the distance of bearing separation on the same shaft.  Or, if only one bearing is used, the distance must not be greater than twice the length of the bearing itself.  Binding will occur if the 2:1 ratio is exceeded.  Besides proper bearing separation, another method of preventing binding is to use a counterbalance. Please see our blog Cantilevered Loads and the 2:1 Ratio for more detail

Frelon J has almost universal chemical inertness. Only molten sodium and fluorine at elevated temperatures and pressures show any signs of attack. FrelonGOLD has fillers that can be attacked by certain harsh chemicals. The standard anodized aluminum shell has good chemical resistance in most industrial applications. The optional 316 stainless steel shell has excellent chemical and corrosion resistance in most industrial applications. Check the chemical reaction chart for specific chemicals. The information provided is for reference only – the user must test specific applications.

The L-10 (L10) life is the number of hours in service that 90% of bearings will survive. Or, conversely, 10% of bearings will have failed in the L-10 number of service hours. L10 life is the preferred term in specifying bearing life and is defined by the American Bearing Manufacturers Association (ABMA). PBC Linear provides load ratings on all our products in order to calculate L10.

The coefficient of friction for filled Teflon can range from .125 to .4 depending on the fillers used.  FrelonGOLD has an average COF of .125, while FrelonJ has an average COF of .12

The 2-sided bearing has only 2 sides with adjustable plugs, the other 2 sides have a Frelon pad. The 4-sided bearing has all 4 sides with bearing plugs.

Plain bearings do not have a dynamic load rating, but are rated by their limiting PV, which is a combination of load over a given surface area and the velocity.

P – pressure or load in pounds per square inc (psi) or kilograms per square centimeter (kg/cm2).
V – velocity or surface speed in feet per minute (fpm or sfm) or meters per minute (m/min).
PV – pressure velocity value, P x V

NOTE: All three parameters must be met by an application for the bearing to perform properly. Max P times Max V does NOT equal Max PV: if one increases, the other must decrease in order to not exceed Max PV.
For a more in-depth look at PV, please see our blog: Calculating PV for a Plain Bearing

Simplicity bearings are designed specifically for linear motion, and are not the ideal choice for high speed rotary applications.  However, when applied properly, Simplicity bearings will work very well in rotary applications. Stationary rotary applications do not allow the heat to be spread over an extended area – it is retained in the ID of the bearing, thus limiting speed and load.  - 40 sfm for precision ID - 140 sfm for compensated ID

−400° F to 400° F (−240° C to 204° C)

−400° F to 400° F (−240° C to 204° C)

¼-28 UNF thread

Recommended lubricants include:  way-lube oils, lightweight petroleum based oils and greases, or 3-in-1 type oils.  Lubrication can greatly increase the performance of a bearing when properly applied, but please refer to the catalog for detailed information.  

Inch series seal materials include Polymod, urethane, and Viton.  Metric seals are available in urethane only.

Inch series 1/2" thru 4", ISO metric 20mm thru 80mm.

Compensated refers to the ID of the bearing. Self-aligning refers to the capability of the bearing within a housing to “rock” in all directions to allow for some shaft deflection and misalignment.

Simplicity bearings are available with two classes of running clearance.  Precision (FL) has the tightest running clearance of approximately .001” (.025mm).  This class is ideal for applications that require high precision.  Compensated (FLC) has additional clearance built into the ID of the bearing to .003” (.0381mm).  The FLC helps to accommodate or “compensate” for slight misalignments.

A compensated fit bearing is looser fit to the shaft diameter, a simple method of checking would be to place both precision and compensated bearings on the shaft the compensated bearing should feel loose by comparison to the standard precision fit bearing.

Refer to Pages 138 - 141 (Installation Simplicity Linear Plain Bearings) in the appendix of the RST (Round Shaft Technology) Catalog

As it relates to linear plain bearing technology stick-slip is often described as a temporary cycle of alternating rest and motion.  If this type of motion is repeatedly observed at the same location, then it is likely that an unknown force is acting upon the system at that location. The most common external forces are caused by misalignment or deflection of the linear shafts or an imperfection in the rail which can be caused by damage. Please see our blog Cantilevered Loads and the 2:1 Ratio for more detail.

Corrosion resistance for recirculating ball bearings is tricky, and PBC does not offer linear ball bearings in stainless steel or other corrosion resistant material. Reference the Round Shaft Technology catalog for available materials. PBC Linear does offer a plain bearing solution with a standard anodized aluminum housing that stands up well to most situations. For more extreme environments, PBC Linear offers the option of a 316 stainless steel housing. Combine this with our available 316 stainless shafting and your application should become corrosion resistant.

Seals are integral on all PBC linear ball bearing products.

Seals are integral on all PBC linear ball bearing products.

A rolling element, such as ball bearing or roller, will offer a lower coefficient of friction than a sliding element (plain bearing).  There are many factors to consider in addition to coefficient of friction, so it’s important for PBC to understand all aspects of the application to offer proper guidance.

No, the IP-G series has a straight OD. The IPS series is self-aligning.

Basic life or L-10 as defined by the International Organization for Standardization (ISO) and American Bearing Manufacturers Association (ABMA), is the life that 90% of a sufficiently large group of apparently identical bearings can be expected to reach or exceed. The median or average life, sometimes called Mean Time Between Failure (MTBF), is about five times the calculated basic rating life. PBC Linear has a broad range of linear motion solutions and a detailed approach to calculating life.

−4° F to 176° F (−20° C to 80° C)

Referencing the catalog, threaded portion that extends from the bottom surface of the pillow block and refers to the thread listed in the table. This is intended for a fastener coming from the bottom and threading into the block from the mounting framework.

The counter bored part of the mounting hole originates from the top, or open side of the block, and this mounting direction is intended for a smaller diameter fastener installed from this side of the pillow block. This ensures the fastener has enough clearance to go all the way thru the threaded section of the block without interference, and thread into the mounting framework.

No, the base material of aluminum will not stand up to the hardened steel ball bearings.

PBC offers 1060 steel linear shafting, which is very similar to 1566.

PBC linear only offers solid round shafting, however, we do have a unique alternative in Simplicity Square Shafting.  This shafting has a unique bearing style with adjustable and replaceable plugs which allow for a completely custom fit. More details on this great product can be found in our catalog.

When producing shafting we run each full length bar through the hardening process, where we have a minimum hardness depth that we assure is maintained for each full bar.  We do not however measure and record the maximum depth of hardness as a standard process. 

The load ratings PBC provides are based on the bearing used on the Shaft Rail Assembly, NOT the shaft and rail.

400 series stainless steel is magnetic because it has a high amount of carbon content.  This allows it to have some corrosion resistance, while steel being able to achieve a case hardness.  If you are looking for the most corrosion resistant series of stainless steel please check out our 316 stainless steel which has very little carbon content.  The downside with 300 series is that it can not be hardened making it a very poor choice when using any rolling element bearing.

The NIL (inch) and NIM (metric) steel shafting is case hardened.

	Case	Core
Tesile	335,000 psi	100,000 psi
Yield	250,000 psi	75,000 psi

Note: Case hardness depth will vary by shaft diameter.  Minimum case hardness depths specified on page 45 for inch series and  page 82 for metric series in the RST (Round shaft Technology) Catalog

	Case	Core
Tesile	341,500 psi	113,805 psi
Yield	182,750 psi	60,900 psi

Note: Case hardness depth will vary by shaft diameter.  Minimum case hardness depths specified on page 45 for inch series and  page 82 for metric series in the RST (Round shaft Technology) Catalog

RMS means root mean square which is an average of peaks and valleys of a material surface.  The square root of the average height deviations from the mean line/surface squared.  Ra stands for roughness average and is simply the average height across the microscopic peaks and valleys.  The linear shafting that PBC Linear manufactures has a surface finish of 8-12 Ra.  This is the recommended range for all Simplicity plain and Simplicity ball products.

It is 6000 series aluminum, tempered to T6.

Maximum length depends on the type of shaft or rail being ordered. Please refer to the Configurator or RST catalog for the maximum lengths of the shaft or rail type you need.

Rollers are permanently installed to ensure accuracy and load capabilities and are not replaceable.

Rollers are permanently installed to ensure accuracy and load capabilities and are not replaceable.

Hevi-Rail is a low carbon rail product and can be welded under good standard MIG welding practices.

Yes. Bearings with pre-welded flange plates are only capable of the system max. Static load capacities shown in the CRT (Cam Roller Technology) catalog. The actual bearings are rated for higher load ratings if configured without the pre-welded flange plate and utilized with customer supplied Hardened Rail HRC 55 (minimum 2.54 mm depth provided).
 

Yes, that is correct. The Welded Bearing/Flange Plate Assembly is rated to accomodate up to the System Maximum Static Load Ratings as published in the CRT (Cam Roller Technology) catalog. These same "System Maximum Static Load Ratings” also apply to the maximum load rating that the Mild Steel U-Channels and I-Channels can accommodate on a per. Roller basis. These are the limiting factors in the system.

No. Redi-Rail underwent a design change in 2006 from a threaded shaft attachment to the current solid stud shafts that are pressed in.
 

No,  PBC Linear only offers Hevi-Rail channels in mild steel.
 
A word of caution: If you’re considering outsourcing Heat Treatment of Hevi-Rail Channels, discuss, review and potentially test samples with a Heat Treatment Specialist for best methods of Heat Treatment.  Improper Heat Treatment methods may result in material distortion, bowing and stress fracturing of Hevi-Rail Channel.
 
The 18MnNb6 material can be heat treated, but usually requires a re-straightening after heat treatment due to warping from the heat treatment if the whole bar is heat treated.
 
Preferred Method - Surface hardening with induction heating with a mechanical clamping or guiding of the bar through the induction coils is what others use that prevents warping.
 
Improper Heat Treatment of Hevi-Rail channels can lead to bowing - twist distortion and stress fracturing of channel.

Yes, PBC Linear has wrenches available for the Commercial Rail. Commercial Rail has an adjustable bearing on each slider allowing the user to customize the fit for every application. You may find the wrenches here.
 

The Redi-Rail product provides a reference notch along the length of the rail to indicate the reference edge.

Compensated carriages will have a dimple, or mark, on the underside.

PBC Linear suggests sand blasting or bead blasting Hevi-Rail channels to remove any signs of oxidation or rust that may have been acquired during shipment and storage. Then follow-up with one of the following coating suggestions:

• PBC Linear suggests priming, painting and / or powder coating the Hevi-Rail Channels. Surfaces on the Hevi-Rail Channel surfaces that are considered Roller Contact surfaces, should be masked prior to applying the coating. Roller contact surfaces must remain bare steel surfaces, but coated with NLGI #2 or Grade 3 Grease to minimize oxidation and corrosion.
• A Hard Chrome Plating or Armoloy (TDC) Thin Dense Chrome Plating can be applied by the customers plating resource to the Hevi-Rail Channels for oxidation and corrosion resistance. An NLGI #2 or Grade 3 Grease should still be applied to the Rollers and Roller contact surfaces of the Rail to increase life expectancy.

Unless purchased as the bearing and flange plate assembly, the bearings must be welded to the framework.

It must be welded or clamped in place.

No, Hevi-Rail components are available in carbon steel only.

The raceways are stainless steel as a standard. However, rollers are not available in stainless steel.

Redi-Rail sliders are rated per slider.

Yes, the V-Guide rail is induction hardened on the roller bearing “V” running surface only to approximately 55Rc and the lower mounting surface of the rail remains soft to provide a machineable surface for installation.

Redi Rail underwent a design change a few years ago in which the threaded stud shaft was replaced by a press fit version onto which the roller was secured by orbit forming the end.

The arrows point in the direction that the radial load should be applied.  The Redi-Rail slider has three rollers, two of which are in contact with one side of the rail and the middle roller is in contact with the other side.  Orienting the load with the arrows offers the greatest load capacity.  

The rolling resistance of the Carriage Roller Bearings is .008~.015, the C.O.F. can be affected by pre-load and operating environments.

.200-.300

14° F to 176° F (−10° C to 80° C)

−32° F to 176° F (0° C to 80° C)

14° F to 176° F (−10° C to 80° C)

14° F to 176° F (−10° C to 80° C)

−30° F to 150° F (−34° C to 65° C)

14° F to 176° F (−10° C to 80° C)

14° F to 176° F (−10° C to 80° C)

To optimize performance, PBC Linear recommends a lubrication expert should be contacted to review applications, however a general purpose grease such as the Shell Alvania #3 or equivalent is typical in lieu of application-specific lubrication.

Redi-Rail requires Button Head Cap Screws (BHCS).

D075: Fath 096286; D100 &D125: 80/20 3279

Each Size Hevi-Rail product is specified with System Max. Static Load Ratings per. Roller for both Radial & Axial Load Capacities which shouldn’t be exceeded when using the Mild Steel U & I Channels that PBC Linear offers.  This System Max. Static Load Rating takes into account operating the Roller on a soft Mild Steel Rail.

Each Size Hevi-Rail Product is also specified with Maximum Bearing Loads (Static and Dynamic) per. Roller which requires the usage of Heat Treated Channels that PBC Linear doesn’t offer.  Note:  Maximum Bearing Loads achievable when used with a hardened rail HRC 55 minimum 2.54mm deep.

The load ratings for the rollers are based on using a hardened rail of 55 Rc minimum.  The rails offered by PBC are hot rolled, mild structural steel and are not hardened.  Therefore, the load ratings are limited by the softer rail material.  PBC does not offer hardened rails.

The overall height dimension given in the catalog is not a physical dimension that can be measured.  It is the theoretical point where the two planes would intersect.  Thus the dimension given in drawing is for Reference Only, and the actual rail will be slightly smaller.  Keep this in mind as you check the height or the rail during inspection, or as you are designing to meet a specific vertical location requirement.

Yes. Utililzing the self lubircating properties of our PTFE coated lead screws and polymer nuts optimizes use in harsh environments that are typically detremental to rolling element ball screw/nut options.

As a rolling element ball screw/nuts typically will back drive when a thrust load is applied to the nut.  Conversly lead screws natural frictional resistance can minimize backdriving by following a good general rule of thumb, that in order to help prevent back driving selecting a screw lead less than 1/3 the diameter of the screw will generally prevent back driving of the nut. 

Backlash is the amount of play or slop in a linear motion system.  PBC Linear offers a constant force technology nut which limits the amount of backlash in a screw driven scenario.  PBC Linear also offers several belt driven systems that offer some advantages over screw driven systems but backlash is not one of those.

Column loading or axial thrust as it is applied to a screw, is the amount of axial force a lead screw assembly can withstand in order to maintain proper performance prior to buckling or excessive deflection. 

Lead Angle is the angle made by the screw pitch helix with a plane perpendicular to the center axis of the screw. 

For lead screw/nut assemblies the sliding friction between the screw and nut will generate heat, excessive heat generation can cause premeature wear and failure of the leadscrew nut.

Pitch diameter is the diamter of a theorectical cylinder that passes therough the threads in such a way that the distance between the thread crests and thread roots are equal. Pitch diameter is commonly measured by using approriately sized pins to rest witin the thread flanks, and then subtracting the pin diamter times 2 from the measurement taken across the three thread wire pins as illustrated in the product catalog. 

PBC Linear uses a proprietary blend of polymers and PTFE to create a self-lubricating, low coefficient of friction nut.  The proprietary blend is treated as confidential and the intellectual property of PBC Linear.  As such, we do not disclose the specifics about the material composition.

-40° F to 248° F (−10° C to 120° C)

Lead screws are available in lengths from 2" to 65" with a standard straightness of .003"/ft.

We use low profile nuts in place of T-nuts due to the small profile of the slots.  The part number for the nut is 6100504 and it utilizes M5 screws (length dependent on your item being clamped).

We utilize two T-nuts, a long and short length…both which fit the side extrusion and top carriage slots.  The short style is part number 6100443.  The long style is part number 6100429.

A belt drive type would best suit this type of application.  A screw type may develop a detrimental property known as “critical speed” due to screw vibration from an unsupported screw at high speed(s).

The PLA is offered with the choice of three types of screws, a ball screw, lead screw, and acme screw.  These are offered in various select screw leads.

The most common types include actuators driven by a belt, screw (ball, lead or acme) or by air (pneumatic).  Other types of actuators include hydraulic, rack and pinion and linear motor driven.

A linear actuator is a device which converts rotary motion (such as from an electric motor) into linear motion and then applys this force in a linear manner.

−32° F to 176° F (0° C to 80° C)

−32° F to 176° F (0° C to 80° C)

−32° F to 176° F (0° C to 80° C)

On the UGT Horizontal belt drive, the pulley pitch diameter is 25.5mm (12.75mm radius); On the UGA Vertical Belt drive, the pulley pitch diameter is 20.7mm (10.35mm radius).

.250" lead, 1.5" diameter.

It is really dependent on the belt and pulley construction, but a general rule of thumb would be 0.004" (100 μm) - 0.008" (200 μm).

• Our MTB series belt driven actuators allow 0.004” (100 μm) for belt drive positional error accuracy deviation.
• Our UG series belt driven actuators allow 0.008” (200 μm) for belt drive positional error accuracy deviation.

A 400 series stainless steel to make it work with the magnetic strips along the opening.

We utilize two T-nuts.  Part number 6100435 is a slot size 6 and fits the slots in the carriage.  Part number 6100436 is a slot size 8 and fits the top & bottom slots on the extrusion body.

Currently, the female (hollow) shaft version of the actuator is not timed between the hollow shaft and the pulley. But with the male shaft version, the internal and external keyways are manufactured at the same time, hence keeping time/orientation between the shaft and pulley.  In the future, the female shaft will be manufactured with the external and internal keyways as timed.

No. There is currently there one size available.

Yes, but this will require additional programming of each shelf height.

Yes. This system can be moved with a pallet jack.

The shelf utilizes a lead screw that will only drive if power is applied.

No air line is needed for the system. However, the cobot setup may require air lines.

The Cobot Feeder job turnover is equal to however fast an operator can swap out trays and a rack. 15 minutes is standard with all the necessary equiptment (new grippers and trays).

1-2 days depending on the application.

Our system works with any CNC/machine and can be tied into functions such as chuck close, cycle start, etc.

Yes. The system is enclosed with light curtains on the openings.

Any application that a cobot/robot currently can do.

72 in x 58 in x 75 in including the rack 54 in x 58 in x 75 in without the rack (L x W x H).

The Cobot Feeder, a ready rack, and 17 trays.

The current trays can hold 50 lb. There is no height limit but we recommend nothing over 18 inches.

8-12 weeks.

The current trays can hold 50 lb. There is no height limit but we recommend nothing over 18 inches.

220V Single Phase with a 30A Recepticle.

The repeatability of the Cobot Feeder will depend on the repeatability of the cobot/robot.

All electrical components are shielded from outside contaminants. Light coolant exposer will have no effect on the system.

The entire system weighs near 1500 lb.

Any robot/cobot with 2 open i/o ports and a reach of at least 800 mm.

Most Standard US pallet jacks will be able to move the Cobot Feeder.

Yes, you can find our certification here.

Yes, you can find our certification here.

No, we do not offer a curved track.

Go to our Configure & Quote page, build your part number, put first name, last name, company and email address in CAD options and Contact Info at the bottom of the configurator. Hit finish and the file(s) and summaries will be emailed to you.

Standard Simplicity® products use aluminum alloy, which is known to have the best corrosion resistance of the high strength aluminum alloys. The sulfuric bath anodizing and nickel acetate sealing provide the best corrosion resistance available in anodized coatings. They can withstand a rigorous 14-day exposure in a 5% salt spray solution at 96°F per military specifications without significant damage. With the coating intact, it is considered to be inert in most fluids with a pH value between 5 and 8. Hard coat anodizing provides the same chemical resistance but is applied to a .002" thickness, providing a more durable surface that will stand up to greater abuse. However, if the coating is penetrated, the resistance is reduced.

For more information please see our Linear Motion Design in Washdown white paper.

On all length products that have mounting holes, there is typically a standard hole-to-hole pattern defined by “X” in our literature.  When PBC cuts these products to the customer’s length specification, we need to know where the customer wants that hole pattern to start relative to the cut end.

Please visit our Sales & Support page.

Dimensions and specifications can be found in the specific product catalog - these are available for download from the PBC website. In addition, CAD models are available for download using PBC Linear's online product configurators.

• Accuracy refers to the ability to achieve a commanded position
• Repeatability refers to the ability to go to any given spot in a consistent grouping

For more information please see our blog: Factors Which Affect Accuracy & Repeatability

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PBC Linear, Remittance Processing, PO Box 7265, Rockford, IL 61126

To set up your ACH/wire transfer for PBC Linear, go to the Payments with Electronic Transfer Page to help complete your transaction. There you will find instructions for both domestic and international transactions. Remember, wiring bank fees are the responsibility of the payor not the payee. All payments are to be in U.S. dollars.

sales@pbclinear.com

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