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MACOR® Material and Machining

Macor is a relatively easy material to machine using ordinary carbide drills, end mills, taps, etc. and doesn’t require post machining firing. Macor-Machinable Glass Ceramic is also unique in that it can withstand 1000°C, has low thermal conductivity and is a good electrical insulator. Macor is often the material of choice because it is easy to machine into complex shapes, doesn’t require sintering and is, readily available even in small quantities.

Whatever your requirement; Macor® stock or machined parts, Contact us Today

MACOR® Material Properties Data

Macor® machinable glass ceramic withstands high temperature while providing tight tolerance capability.
Special Features
Excellent physical properties
High dielectric strength
Electrical resistivity
Non-porous and non-shrinking
Machined into complicated shapes and precision
  parts using ordinary metal working tools
 
Properties
   
Temperature Limit 1000° C
Dielectric Constant, 1 Khz at 25° C 6.03
Dielectric Strength 40KV/mm
DC Volume Resistivity at 25° C >10 ohm-cm
Thermal Conductivity at 25° C 1.46 W/m° C
Coefficient of Expansion 25-300° C 93 x 10 /° C
Density, g/cm 2.25
Modulus of Elasticity at 25° C 64 GPa
Porosity 0
Image of Ceramic Manufactured Parts - Group 2
   
 Available as Finished Parts Today  
Available in bulk shapes or fully machined
Machinable to tight tolerances with standard metal working tools
No firing required after machining
 
 Applications
Electrical or Thermal Insulator
Structural Components
Semi-Conductor Processing
Electrical and Opto-Electronic Equipment
Many Other Uses
 
 
MACOR®
 
 
Machinable Glass Ceramic
is MACHINABLE with no ordinary metal working tools
allows FAST TURNAROUND, no post firing required
holds TIGHT TOLERANCES, up to .00005"
withstands HIGH TEMPERATURE, up to 1000°C (no load)
is CLEAN, no outgassing and zero porosity
 
 
Properties
MACOR® Machinable Glass Ceramic has a continuous use temperature of 800°C and a peak temperature of 1000°C. Its coefficient of thermal expansion readily matches most metals and sealing glasses. It is non-wetting, exhibits zero porosity, and unlike ductile materials, won't deform. It is an excellent insulator at high voltages, various frequencies, and high temperatures. When properly baked out, it won't outgas in vacuum environments.
 
Machining
Machining tolerances are surprisingly tight, up to .0005". It can be machined to a surface finish of less than 20µin.-AA. Configurations are limited only by available equipment and the experience of the machinist.
 
Sealing, Joining and Metalizing

MACOR® MGC can also be joined or sealed - both to itself and to other materials - in a number of ways: metalized parts can be soldered together and brazing has proven an effective method of joining the material to various metals; epoxy produces a strong joint, and a sealing glass creates a vacuum tight seal. Even a straight-forward mechanical joint is possible.

It can be thick film metalized using metal links, or thin film metalized by sputtering.

 

Applications

 
Ultra-High Vacuum Environments
MACOR® Machinable Glass Ceramic is used as an insulator or coil support and for vacuum feed-throughs. In these applications, the conductive materials are supported by the MACOR® MGC part and a compatible sealing glass is used to produce a vacuum-tight, hermetic seal.
 
Constant Vacuum Applications
MACOR MGC parts are found in spacers, heaters and windows for microwave tube devices and as sample holders in field ion microscopes.
 
Aerospace Industry

Over 200 distinctly shaped MACOR® MGC parts can be found on America's reusable Space Shuttle, Orbiter. Retaining rings of MACOR MGC are used at all hinge points, windows and doors.

Also, large pieces of MACOR® glass ceramic are used in a NASA spaceborne gamma radiation detector. For this application, frame corners are joined by a combination of machined (butt-lap) mechanical joints and a sealing glass.

 
Nuclear-Related Experiments
Since MACOR MGC is not dimensionally affected by irradiation, small cubes of the material are machined to a tolerance of one micron and used as a reference piece to measure dimensional change in other materials.
 
Welding Nozzles
Welding equipment manufacturers are using MACOR® MGC as a nozzle on the tips of oxyacetylene torches. The material's non-wetting characteristic means molten particles won't adhere to and decrease the effectiveness of the nozzle.
 
Fixtures
MACOR MGC is used as an electrode support and burner block in several industrial high heat, electrical cutting operations due to its low thermal conductivity and excellent electrical properties.
 
Medical Equipment
Producers of medical components are intrigued by MACOR® MGC's inertness, precise machinability and dimensional stability.
 
With MACOR® Machinable Glass Ceramic (MGC), fabrication is fast because it can be machined into complicated parts with ordinary metal working tools, quickly and inexpensively, and it requires no post firing after machining. That means no frustrating delays, no expensive hardware, no post fabrication shrinkage, and no costly diamond tools to meet specifications.
 
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Ceramic Parts Image 2
 
 
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The Point is this:
When you need the performance of a technical ceramic (high use temperature, electrical resistivity, zero porosity) and your application demands the ready fabrication of a complicated shape (quickly, precisely, privately), look at MACOR® MGC. It will lower costs and substantially reduce the time between design and actual use.

 

Properties

Macor - Termal, Mechanical, Electrical, Chamical - Properties table Macor Manufactured Part

 

Technical Data

 
The general characteristics of this material described below were derived from laboratory tests performed by Corning from time to time on sample quantities. Actual characteristics of production lots may vary.
 
Macor Techinical Information Image
 
MACOR® Machinable Glass-Ceramic is a product of Corning Glass Works. San Jose Delta, authorized Stocking Distributor-Fabricator, converts the basic material into a wide range of standard sizes which allow the user to conveniently machine the final part. San Jose Delta can also custom-fabricate MACOR® Machinable Glass-Ceramic to the customer's drawing.


 
Round Rod Sizes
 
TOLERANCE ON ROD LENGTH:
Minus 1/16" (1.59mm) plus an unspecified amount
FRACTIONAL DIAMETER
6"DECIMAL DIAMETER & TOLERANCE
METRIC DIAMETER & TOLERANCE
     
1/8"
.125"
+.250"
-.000
3.18
+0.7
-0mm
3/16"
.188"
4.76
1/4"
.250"
6.35
3/8"
.375"
+.050"
-.000
9.53
+1.3
-0mm
1/2"
.500"
12.7
5/8"
.625"
15.88
3/4"
.750"
19.05
1"
1.000"
25.4
1-1/4"
1.250"
31.75
1-1/2"
1.500"
+.250"
-.000
38.1
+6.4
-0mm
2"
2.000"
50.8
3"
3.000"
76.2
4"
4.000"
101.6
6"
6.000"
152.4

 

Sheet Sizes

 
FRACTIONAL THICKNESS
DECIMAL THICKNESS & TOLERANCE
METRIC THICKNESS & TOLERANCE
     
1/8"
.125"
+.250"
-.000
3.18"  
+0.7
-.0mm
1/4"
.250"
+.050"
-.000
6.35
+1.3
-0mm
1/2"
.500"
+.060"
-.000
12.7
+1.52
-0mm
3/4"
.750"
19.05
1"
.1.000"
25.4
1-1/4"
.1.250"
31.75
2"
.2.000"
50.8
 

 

Other Information

 
Cost-Savings For greatest economy, the user should compare prices of all listed sizes and shapes that would yield the desired finished items. Due to the way MACOR® Machinable Glass-Ceramic is named an equivalent amount of material in the form of smaller pieces sometimes costs less than a single larger piece. Also, in some cases, thicker or larger diameter pieces cost less than similar thinner or smaller diameter pieces.
   
Non Standard Items
"Machining Stock"
Please ask for special quotations which do not appear on tis price list. Various shapes including rectangles, cylinders and discs in sizes that are between larger or smaller than listed sizes may be furnished. Special items often cost less than the nearest standard sizes.
   
Custom Fabrication Pricing for precision blanks or fully fabricated parts made to customer drawing will be furnished on request.
 

MACOR® Machining Instructions

Key factors for successful machining are proper machining speeds and coolant.

MACOR® Machinable Glass Ceramic can be machined with high speed steel tools, but carbide tools are recommended for longer wear.

Achieve the best results by using a water soluble coolant, such as Cimstar 40 - Pink, especially formulated for cutting and grinding glass or ceramics.

No post firing is required after machining.

 
Grinding
Diamond, silicon-carbide or aluminum-oxide grinding wheels can be used.
 
Polishing
Start with loose 400-grit silicon carbide on a steel wheel. For the final polish, use cerium oxide or alumina on a polishing pad for glass or ceramics. A 0.5µin.-AA finish can be achieved.
 
Sawing
Use a carbide grit blade at a band speed of 100 fpm. An alternative is a silicon carbide or diamond cut-off wheel.
 
Turning
Cutting speed 30-50 sfm
Feed rate .002-.005 ipr
Depth of cut .150-.250 in.
 
Milling
Cutting speed 20-35 sfm
Chip Load .002 ipt
Depth of cut .150-.250 in.
 
Drilling
Drill size Spindle Speed Feed Rate
1/4 in. 300 rpm .005 ipr
1/2 250 .007
3/4 200 .010
1 100 .012
2 50 .015
Allow at least .050" of extra material on the back side for breakout. This excess can be removed after drilling.
 
Tapping
Make clearance holes one size larger than those recommended for metals. Chamfer both ends of the hole to reduce chipping. Run the tap in one direction only. (Turning the tap back and forth can cause chipping.) Continuously flush with water or coolant to clear chips and dust from the tap.
 
Composition

MACOR® Machinable Glass Ceramic is a white, odorless, porcelain-like (in appearance) material composed of approximately 55% fluorophlogopite mica and 45% borosilicate glass. It has no known toxic effects; however, the dust created in machining can be an irritant. This irritation can be avoided by good housekeeping and appropriate machining techniques. The material contains the following compounds:

   
  Approximate Weight %
Silicon - SiO2 46%
Magnesium- MgO 17%
Aluminum - SiO2 16%
Potassium - K2O 10%
Boron - B2O3 7%
Flourine - F 4%
 

Macor Image Magnified
Microstructure of MACOR® MGC 5000X magnification

Randomly oriented mica flakes in the microstructure of MACOR® MGC are the key to its machinability.

 
Macor Image 1
 
Macor Image 2
 
Macor Image 3
 
Macor Image 5
482 Sapena Court, Santa Clara, California  95054
Fax: 408-727-6019, Email: sales@sanjosedelta.com.
Copyright © 2012 San Jose Delta Associates, Inc. (408) 727-1448. All Rights Reserved
MACOR® is a registered trademark of Corning Incorporated, Corning, NY