Macor
With MACOR ® Machinable Glass Ceramic (MGC), fabrication is fast because it can be machined into complicated shapes and precision 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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Applications
Why should I use MACOR?
MACOR Composition
MACOR ® - Machinable Glass Ceramic
- Is MACHINABLE with ordinary metal working tools
- Allows FAST TURNAROUND. No post firing required
- Holds TIGHT TOLERANCES, up to .0005"
- Withstands HIGH TEMPERATURES, up to 1000oC (no load)
- Is CLEAN, no outgasing and zero porosity.
Properties
MACOR ® Machinable Glass Ceramic has a continuous use temperature of 800oC and a peak temperature of 1000oC. Its coefficient of thermal expansion readily matches most metals and sealing glasses. It is nonwetting, 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 that 20µin. and polished to a smoothness of 0.5µin.-Ra. 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 sealing glass creates a vacuum tight seal. Even a straightforward mechanical joint is possible.
It can be thick film metalized using metal inks, or thin film metalized by sputtering.
For more information download PDF in related links to the right.
Macor 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 pas and a compatible sealing glass is used to produce a vacuum-tight, hermetic seal
Constant Vacuum Applications
MACOR MGC parts are found in spacers, headers, 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 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
Sine MACOR MGC is not dimensionally affected by irradiation, small cubes or 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 manufactures are using MACOR MGC as a nozzle on the tips of oxyacetylene torches. The material's nonwetting 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.
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Why should i use MACOR?
When you need the performance of a technical ceramic (high 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.
Machining
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 ceramic.
No post firing is required after machining.
Sawing
Use a carbide grit blade at a band speed of 100fpm. An alternative is a silicon carbide or diamond cut-off wheel.
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.
Turning
Cutting speed 30-50 sfm
Feed rate .002-.005 ipr
Depth of cut .150-.250in
Milling
Cutting speed 20-35 sfm
Chip Load .002 ipt
Depth or cut .150-.200 in.
Drilling
| Drill Size | Spindle Speed | Feed Rate |
|---|---|---|
| ¼ in. | 300 rpm | .005 ipr |
| ½ | 250 | .007 |
| ¾ | 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. Turn 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.
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MACOR 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.
MACOR contains the following compounds:
| Material | Approximate Weight |
|---|---|
| Silicon - SiO2 | 46% |
| Magnesium - MgO | 17% |
| Aluminum - Al2O3 | 16% |
| Potassium - K2O | 10% |
| Boron - B2O3 | 7% |
| Fluorine - F | 4% |
| Aluminum Silicate | |||
|---|---|---|---|
| Property | Units | M-120F | Macor® |
| Color | Tan to Pink | White | |
| Density | G/CC | 2.3 | 2.52 |
| Porosity | % Water Absorption | 3 | 0 |
| Flexural Str. | KPSI | 9 | 13 |
| Compressive Str. | KPSI | 40 | 50 |
| Hardness | Knoop | 500 | 250 |
| Thermal Cond. | W/M°K W/M°C | 1.3 | 1.46 |
| Coefficient of Linear Thermal Expansion | 25° to 300°C 25° to 1500°C (X10-6) | 3.3 | 9.3 |
| Maximum Use Temp. | °C | 1150 | 1000 |
| Vacuum Atmosphere | °C | - | |
| Dielectric Str. | Volts/Mil V/MMX 103 | 100 | 1000 |
| Volume Resistivity | ohm-cm 25° | >1014 | >1016 |
| Dielectric Constant | 1 MHZ 25°C 1 KHZ 25°C | 5.3 - | 6.03 |
| Loss Factor | 1 MHZ 25°C 1 KHZ 25°C | .053 | .0047 |
ONLINE ORDERING AND QUOTATION SYSTEM
Ordering your standard size MACOR products is now a whole lot quicker and easier. New and current customers can Apply for a Customer Account TODAY and make the order process even faster.
