SM4 060 050 RCF - Straight M4 CMM Stylus 6mm Ruby Ball, 50mm Carbon fiber, EWL 34mm

• Thread Size: M4
• Ball Size (DK): 6.0 mm
• Ball Material: Ruby
• Stem Length (LK): 50.0 mm
• Stem Material: Carbon Fiber
• Effective Working Length (KML): 34.0 mm
• Stem Diameter (DS): 4.5 mm

CMM Stylus Equivalents:

• Renishaw A-5003-7306
• Q-Mark TM4-6053-G
  

CMM Stylus Information:

• Application: CMM Part Inspection – Machine Tool Probe
• Part Number: SM4 060 050 RCF
• Country of Origin: Germany
• Brand: InspectShop.com
• Condition: New: A brand-new, unused, unopened, undamaged item in its original packaging (where packaging is applicable)

Straight CMM Styli

The straight CMM stylus is the simplest of styli, and is designed to get in direct contact with a simple feature on the part or element to inspect. The straight stylus design is comprised of a few elements such as a highly spherical ball available in different materials and a choice of stem material. Each combination of probing element and stem material will have their advantages for particular inspection applications.

In the case of a CMM stylus with ruby, industrial rubies are used to prevent and/or minimize wear because of their extremely hard characteristics. Also, their low density and low mass make them the ideal material to reduce false probe triggers during part inspection that can occur when your CMM or machine tool moves or vibrates.

The stems on which the touch elements are mounted will also have an impact on your application. A range of different materials and shapes are available at InspectShop.com such as stainless steel for reduced cost, tungsten carbide, ceramic and carbon fiber for ultimate strength and minimal weight. In any case, the ruby CMM stylus is simple, efficient and cost effective for the most common inspection applications.

The size of the feature to measure will determine the size of the ball to use and the clearance to inspect that particular feature will dictate the ideal Effective Working Length (commonly known as EWL) for your stylus. InspectShop.com offers you multiple choices of element sizes and styli stem lengths to accommodate all your inspection needs

Rules of thumbs for choosing your CMM stylus

A few simple rules for can be followed to make sure you select the best CMM stylus to maximize accuracy for most probing and inspection applications:

Keep the stylus ball as large as possible

While the size of the features drives the size of the ruby ball to use, it is good practice to keep the styli ball as large as possible and the stem as short as possible. The advantage of using the largest ruby ball possible is to reduce the impact of the surface finish and imperfections of the part while providing maximum clearance between the ruby ball the stem and maximizing stiffness and rigidity over longer working length.

In summary, there are several reasons for choosing the largest ruby balls possible for your styli:

• Maximizing clearance between the stem and the contact element, reducing chances of false triggers caused by 'shanking out' on the styli stems, and increasing the effective working length (EWL)
• Reducing the effect of the surface finish of the component being inspected
• Increasing overall stiffness of the styli by using larger balls allowing for larger styli stems diameter

Which choose ruby for your CMM stylus material?

The simple answer is that ruby is one of the hardest known material. Its natural toughness and hardness, makes it the ideal CMM stylus material to guarantee a long product life without wearing of and damaging the surface of the component during part inspection.

Synthetic ruby styli are wildly used in industrial applications and are man made from up to 99% pure aluminium oxide which is then turned into crystals, which are then machined into a perfectly spherical shape. Ruby balls are exceptionally smooth on the surface, have great compressive strength and a high resistance to mechanical corrosion.

There are however a few inspection applications where ruby is not the preferred material, such as:

heavy duty inspection applications on aluminium. Because the material attracts, a phenomenon known as “adhesive wear” can occur which involves build up of aluminium from the surface onto the ball. A better ball material for such applications is silicon nitride.

The second is in heavy duty inspection applications on cast iron. Interaction between the two materials can result in “abrasive wear” of the ruby ball surface. For such applications, Zirconia balls are recommended. 

Keep CMM styli short

The more the stylus bends or deflects, the lower the accuracy of the inspection. Probing with the minimum stylus length for your inspection application is the best option.

Minimise joints in your CMM Stylus assembly

Every time you join styli and extensions, you introduce potential bending and deflection points into the assembly. Try, wherever possible, to keep to the minimum number of pieces as low as possible for your application.

Terminology:

Overall length (DK)

The overall length is typically measured from the rear mounting face of the CMM stylus to the centre of the ball.

Effective working length (EWL)

This is measured from the centre of the ball to the point at which the stem will contact against the feature when probing 'normal' to the part.