Established in 1952

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The 3 Inch X 3 Inch Pre-assembled Kinematic Platform

	Specification Files Part Number PDF IGES Solid Works KP-3-3   KP-3-3 KP-3-3 KP-3-3-P KP-3-3-P KP-3-3-P KP-3-3-P KP-3-3-T KP-3-3-T KP-3-3-T KP-3-3-T KP-3-3-CS KP-3-3-CS KP-3-3-CS KP-3-3-CS SP-3-3 SP-3-3 SP-3-3 SP-3-3 The 3-inch by 3-inch (76 x 76 mm) Kinematic Platform is now available as a plug and play device.
3" X 3" Kinematic Platform

3" X 3" Kinematic Platform, Top and Bottom

This extremely small platform will carry an enormous 50-pound ( 23 kg ) load. This is a petite design, but it is not a toy Its robust construction uses a one half-inch (1/2", 12.7 mm ) thick aluminum plate. The overall height of this Kinematic platform from the base to the top is one and one eight inches (1 1/8", 1.125", 28.6 mm). In staying with an industrial design, this platform uses three large, three-quarters of an inch (3/4", 19mm) diameter spheres on the lower platform.

These spheres are not ordinary commercial steel bearing balls that are prone to rust and very susceptible to fretting. Our spheres are made of extremely fine-grained, high chrome, high carbon, stainless steel, that is hardened to 58 HRC minimum.

Their sphericity and surface quality are precision lapped to AFBMA instrument quality grade 10.

This quality provides repeatability that can be orders of magnitude better than the conventional commercial product.

The Kinematic seats in the upper platform use three pairs of precision cylinders that form three vees. These cylinders are ground and precision lapped to a surface texture that is less than 1.0 microinch (25 nanometers) Ra. These six cylinders are glued into three precision-machined trenches with a ceramic filled epoxy to provide absolute rigidly. The six cylinders are made of the same material and processed in exactly the same manner as the ultra precise balls

This contrasts with commercial dowel pins that are used in competitive products. These ground only carbon steel dowel pins are prone to rust and are very susceptible to fretting, which is one of the major problems, of Kinematic Couplings.

This extremely small platform will carry an enormous 50-pound ( 23 kg ) load.

Magnetic Preload

To add versatility to this platform, we offer an optional magnetic preloading arrangement. Both upper and lower platforms have a five-eighths of an inch ( 5/8", 0.625", 15.9mm ) by 18 threads per inch hole tapped through their center. These tapped holes will accept our standard rare earth super magnets (our part number 625-18-MG-N or 625-18-MG-S) at $23.62 each, or a high magnetic permeability plug (our part number 625-18-HPD) at a cost of $8.62 each. The price of the magnetic preload kit (our part number 625-18-MG-KIT), including two magnets, one north seeking (our part number 625-18-MG-N) and one south seeking (our part number (625-18-MG-S) and a high perm plug (our part number 625-18-HPD) at cost of $ 55.80 for each complete kit.

The beauty of this design is that the magnetic pre-load can be used or not used. If it is used, it can be adjusted from one ounce to 14 pounds (6.4 KG). For a heavy pre-load two super rare earth magnets are used. There is a north-seeking magnet (part number 625-18-MG-N) at $23.62 each, in one platform and a south-seeking magnet (part number 625-18-MG-S) at $23.62 each, in the other. For lighter preloading, a single magnet is used in one platform and a high magnetic permeability plug (our part number 625-18-HPD) at $8.62 each, is used in the other. This arrangement reduces the strength of the magnetic field by one half.

When no magnetic preload is desired, the Kinematic platforms are used without the magnets.The top surface is ground flat.

There are two standard versions of the upper Kinematic platform. One version has a plane flat upper surface that our customers can custom tailor to hold the apparatus they want to mount on it, or we will bid machining the details to your blue print or rough sketch (our part number KP-3-3-P). The second version of the upper platform has ten one-quarter inch (6.3 mm) by 20 threads per inch drilled and tapped holes in the top surface to facilitate mounting the required apparatus. The top surface is ground flat. This version of the upper platform is (our part number KP-3-3-T) at a cost of $ 92.00 each.

Part No.: KP-3-3-T, Upper Plate

The Kinematic seats in the upper platform use three pairs of precision cylinders that form three vees. These cylinders are ground and precision lapped to a surface texture that is less than 1.0 microinch (25 nanometers) Ra. These six cylinders are glued into three precision-machined trenches with a ceramic filled epoxy to provide absolute rigidly. The six cylinders are made of the same material and processed in exactly the same manner as the ultra precise balls.

Lower Kinematic Platform

There are also two standard versions of the lower platform.

The first is a three inch by three inch (3" X 3", 76 mm X 76 mm) by one half-inch (1/2", 12.7 mm) thick aluminum plate.

It is made for custom mounting, to the mating structure, and has three one-quarter-inch ( 1/4", 6.3 mm) diameter counter bored holes that will accept standard one-quarter-inch ( 1/4" ) or 6 mm diameter socket head cap screws.

This version of the lower platform is (our part number KP-3-3-CS) at a cost of $ 49.00 each.

Lower Bar Plate and a Plain Upper Plate

The second standard version of the lower platform consists of three individual pieces of one inch ( 1", 25.4 mm) wide, one half-inch (1/2", 12.7 mm) thick and four-inch (4", 101 mm) long bars. Each bar has a super accurate, three quarter inch ( 3/4", 19 mm ) diameter sphere, rigidly mounted on one end. There is a three-inch (3", 77 mm) long, recessed slot that will accept a one-quarter inch or six millimeter (1/4", 6mm ) socket head cap screw opposite this ball.

This version is the truly a universal design. It will adapt to any optical table or tee slotted arrangement.Simple drilled and tapped hole will securely fix it to its mating structure.

Magnetic Preload

To add versatility to this platform, we offer an optional magnetic preloading arrangement. Both upper and lower platforms have a five-eighths of an inch ( 5/8", 0.625", 15.9mm ) by 18 threads per inch hole tapped through the center of all the platforms that will accept our standard five eighths of an inch ( 5/8", 0.625", 16 mm ) diameter 18 threads per inch adjustable super magnets(part number 625-18-MG-N or S), at a cost of $23.62 each. This design is far superior to embedded naked magnets.

These tapped holes will accept our standard rare earth super magnets (our part number 625-18-MG-N or 625-18-MG-S) at $23.62 each, or a high magnetic permeability plug (our part number 625-18-HPD) at a cost of $8.62 each. The price of the magnetic preload kit (our part number 625-18-MG-KIT), including two magnets, one north seeking (our part number 625-18-MG-N) and one south seeking (our part number (625-18-MG-S) and a high perm plug (our part number 625-18-HPD) at cost of $ 55.80 for each complete kit.

The beauty of this design is that the magnetic pre-load can be used or not used. If it is used, it can be adjusted from one ounce to 14 pounds (6.4 KG). For a heavy pre-load two super rare earth magnets are used. There is a north-seeking magnet (part number 625-18-MG-N) at $23.62 each, in one platform and a south-seeking magnet (part number 625-18-MG-S) at $23.62 each, in the other. For lighter preloading, a single magnet is used in one platform and a high magnetic permeability plug (our part number 625-18-HPD) at $8.62 each, is used in the other. This arrangement reduces the strength of the magnetic field by one half.

When no magnetic preload is desired, the Kinematic platforms are used without the magnets.

Sub Plates

An additional feature of the 3 x 3 pre assembled kinematic platform is the availability of sub-plates. These inexpensive sub-plates are the full 3-inch by 3 inch (76.2 mm by 76.2 mm) and are one-quarter inch (1/4", 6.3 mm) thick. They are precision ground flat and parallel.

There are three counter sunk, one quarter inch (1/4", 6.3 mm) diameter holes, that exactly match the hole pattern. This inexpensive sub-plate (our part number SP-3-3) has a plain flat upper surface that can be custom tailored to hold your payload. They are priced at $17.00 each.

Tie Down Screw Kit

A tie-down screw kit consisting of a variety of one-quarter inch (6.3 mm), by 20 threads per inch hardware (part number 250-20-TD) is available for $17.00 per lot. This kit consists of the following: screwdriver slotted (or small coin) cap screws 6 pieces one inch (25 mm) long 6 pieces one and one half inches (38 mm) long 6 pieces two inches (51 mm) long 4 pieces of continuous threaded stock 9 inches (230 mm)long 8 pieces of heavy washers 8 pieces of heavy duty hex nuts 8 pieces of wing nuts

Cost Summary

The entire cost of the complete two piece set of the 3" X 3" plain platform with the solid 3" X 3" base platform is $111.00 for each complete set.

If the magnetic preload kit (our part number 625-18-MG-KIT) is desired, add $55.80.

The cost of the complete two piece set of the 3" X 3" drilled and tapped platform, with the solid 3" X 3" base is $ 127.00 each complete set.

The entire cost of the 3" X 3" plain platform with the four bar lower platform kit is $ 124.00 for each complete set.

The entire cost of the 3" X 3" drilled and tapped platform, with the four bar lower platform kit is $ 160.00 each complete set.

Vertical Mounting

An additional feature of the 3" x 3" Kinematic platform is that it can be used in a vertical position for light loads, if it is adequately pre-loaded.

Mechanical Clamping

A mechanical clamping technique has been developed for this platform so that it can be used in off axis, high load or, fail-safe, situations. This mechanical clamping scheme is viable in high vibration environments.

This mechanical clamping kit consists of a 5/8-inch (16 mm) diameter plug with 18 threads per inch, on the O.D., (our part number 625-250-PLUG); at a cost of $12.00 each, that screws into the center hole in the lower platform. It has a 1/4-inch (6.3 mm) by 20 threads per inch, center hole to accept a length of continuous threaded stock. A similar plug with a .280-inch (7.1 mm) diameter clearance hole, our part number 625-280-PLUG at a cost of $12.00 each, screws into the upper platform. A rather long piece of continuous threaded stock passes through this hole and through a self-aligning spherical tilt, part number 75-ST-270 at a cost of $32.00 each. This spherical tilt is used to isolate any X-Y-Z misalignment of the clamping force. The entire assembly is tied together by a one-inch ( 1", 25.4 mm ) diameter, knurled clocking nut (our part number 250-20-CN), at a cost of $19.00 each. This stainless steel clocking nut includes a ball thrust bearing which decouples the torque of the clamping. A wing nut and washer are supplied to be used as a jam nut, under conditions of moderate vibration. The entire kit, including all of the parts required is part number KP-CLAMP at a cost of $75.00 total.

Spring Load

When a spring-loaded force is preferred, for pre-loading, a very simple arrangement will suffice. By just insert a spring, of the desired stiffness, between the clocking nut and the spherical tilt or between the bottom of the spherical tilt and the platform the job is complete.

Custom Versions

Custom versions of this 3" X 3" platform will be quoted. The platforms can be supplied, hard anodized or nickel-plated, and or with reference surfaces flat lapped.

The same basic design can be built with cemented tungsten carbide, kinematic components that will give greater load carrying capacity, higher resonant frequency and more accurate repeatability. It should also be noted that cemented tungsten carbide components will carry very heavy loads, with no sign of fretting.