Machining / Grinding BK7 Glass

CiDRA® Precision Services, LLC has years of experience manufacturing micron level tolerance products from BK7 glass. We leverage our in-depth dicing, drilling, milling, grinding, and polishing capability to manufacture the highest quality BK7 products. For those applications with exacting optical requirements, CiDRA® Precision Services, LLC has the ability to clean, polish, and apply coatings.

Whether you need prototypes or volumne production, CiDRA® Precision Services, LLC is here to help. Please contact us to discuss your applications.

About BK7 Glass

BK7 is one of the most common technical optical glasses primarily because it offers a broad optical transmission range with excellent mechanical properties and very low bubble inclusion.   BK7 is a relatively hard borosilicate glass that possesses good scratch resistance.   Because of its stable chemical properties, no special treatment is required to grind and polish BK7. 

BK7 Glass Applications

  • Optical components
  • Optical Blanks

BK7 Properties

 

Units

BK7
Softening Point C 715
Annealing Point C 550
Strain Point C 624
Max Use Temperature C 350
Thermal Conductivity W/(m K) 1.1
Specific Heat J/(kg C) 879
Coefficient of Thermal Expansion 1/C (x10^-6) 7.10
Moh Hardness 5
Knoop Hardness kg/mm^2 520 - 610
Density g/cm^3 2.51
Compressive Strength MPa
Tensile Strength MPa
Bending Strength MPa
Young's Modulus GPa 85
Poisson's ratio 0.21
Dielectric Strength kv/cm
Dielectric Constant (@1MHz)
Dielectric Loss Tangent
Resistivity ohm/cm
Usable Transmission Range um 0.35 to 2.0
Refractive Index (@550nm) 1.52
The information provided in this table is for room temperature only, and is a compilation of publicly available data.  This information is provided for comparison purposes only, and is not intended to be warrantable.   Further, CiDRA® Precision Services, LLC disclaims any and all liability from errors, inaccuracies, or omissions.

 

Please contact us if you would like to discuss your BK7 dicing, drilling, milling, grinding, polishing or any other machining applications.