How to increase the Furnace load up to +100 %

Joerg Demmel • October 17, 2019
Successful CFC Fixture Applications
or
How to increase the Furnace load up to +100 %
or
“Finding the needle in the haystack”

The design of a new CFC Fixture is the most crucial requirement for the success of a new Fixture Application in terms of quality and efficiency.

Figure 1 shows the 3 design levels and their advantages. Level III is most difficult to achieve, but has the highest economic benefits.

High Temperature Concept | Figure 1: Three CFC Fixture or Rack Design levels | 20191027

Figure 1: Three CFC Fixture or Rack Design levels by High Temperature Concept


Please note that Carbon Fiber reinforced Carbon or CFC is still an outstanding, unreached material. Some details see Newsletter #1. The main 3 material properties which make this material so outstanding and recommend it as a Fixture Material are (CFC Sigrabond Performance ® compared to heat resistant cast austenitic steel like ASTM A297-HK at 20 and 1,000 oC):

 

1. Low density of about 1.5 compared to 7.8 to 7.5 g/cm3

2. Low C. T. E. of about -0.5 to 0.8 compared to 11 to 18 x 10-6 K-1

3. Extremely high specific strength of about 200 to 233 compared to 65 to 11 N / m g


But, why is it still a great challenge for technicians and engineers designing ingenious Fixtures for commercial or captive heat treaters? An attempt at explanation is that there are some contradictory requirements for material developers and designers on the one hand, and users in industry in the rough heat treatment area and its surroundings on the other hand.


Unlike many competitors, we worked for many years in the user industry in responsible positions and/or went to many customers with heat treatment workshops. Many Fixture designs were successfully realized for our customers, mainly in the Industries of Tooling, Automotive, Electronics, or Aerospace.


The key to success or “the needle in the haystack” is the just mention combination of knowledge and experiences. Mainly with the aim reducing work piece distortion most effective, in some cases with the result of reduced hard machining.


Another unique feature is that the President and founder of High Temperature Concept TM Dr. Jorg Demmel wrote his doctoral thesis just on this field over “Scientific aspects of the development of new workpiece carriers for high temperature processes made of fiber composite ceramics CFC and other high temperature materials”.

 

The consequence is, that of course our aim is to be best-in-class, means, compared to Figure 1, our approach is design level III. Or, in other words, our Fixture design pays off most! Compare Figure 2.


High Temperature Concept | Figure 2: Best-in-class Approach by CFC Fixture design | 20191027

Figure 2: Design levels and competitors by High Temperature Concept


As proof of the written passages above, we would like to introduce just two CFC Fixture applications, both of which have been successful in the industry for over 15 years and pay off.


Figure 3 shows CFC-Fixtures for Brazing of heat exchangers in a vacuum process.


Figure 4 shows CFC-Fixtures for Allen keys in an Annealing process in an atmosphere process with oil quenching.

High Temperature Concept | Figure 3: Level II CFC Fixture Application for Brazing, Modine Europe | 20191027

Figure 3: Level II CFC Fixture Application for Brazing, Modine Europe


High Temperature Concept | Figure 4: Level III CFC Fixture Application for annealing, including oil quenching, Wiha, Germany | 20191027

Figure 4: Level III CFC Fixture Application for Annealing incl. oil quenching, Wiha


Figure 5 shows the main advantages of CFC Fixtures (green columns) compared with state-of-the-art cast steel Fixtures (red).





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High Temperature Concept | Figure 5: CFC Fixture and Rack Advantages by Experience | 20191027

Figure 5: CFC Fixture and Rack Advantages (min./max. values of the bars depending on customer situation and investment volume; by experience; © High Temperature Concept TM, Dr. Jorg Demmel)



Last but not least, CFC Fixtures with low weight and C.T.E. open a new perspective of heat treatment integration in the process chain between soft and hard machining. Automatic part handling can be reached effectively mainly in large-scale productions like in the automotive industry. It is reported not only by the author, but as well in /1/, that in some cases “hard machining can be eliminated completely”. This is explained by the just mentioned CFC properties and its high thermal shock and chemical resistance, and the high dimensional accuracy and shape stability of CFC Fixtures, Racks and Trays, which results in a much better process control. An increased process reliability with less product distortion is not only reported by the author for many CFC Fixture applications of heat-treated precision parts, but also mentioned for the case hardening of large surface gear parts with low-pressure carburizing (LPC) combined with high-pressure gas quenching (HPGQ) in /1/.

 

CFC Fixtures play an important role in controlling distortion, increasing net load, reducing multiple workpiece handling, and decreasing fixture life cycle costs. Therefore, overall manufacturing costs can be significantly reduced.

 

Ask for the difference!

It pays off soon.


Get your custom quote today Request Quote.


Contact Us:

 +1 941 299 9191

info@High-Temperature-Concept.com

www.high-temperature-concept.com



Sources:

J. Demmel, dissertation „ Scientific aspects of the development of new workpiece carriers for high temperature processes made of fiber composite ceramics CFC and other high temperature materials “, TU Freiberg, Germany, 2003, and
Dr. J. Demmel oral presentation „Advanced CFC
-Fixture Applications, their scientific challenges and economic benefits“, 30th Heat Treat,Detroit, Michigan, 15th October 2019, and
/1/
R. Terjung: CFC-Fixtures – Quality fixturing for vacuum heat treating, 4-2016, in: Heat processing, p. 73-77

By Joerg Demmel June 12, 2025
“𝗖𝗙𝗖-𝗙𝗶𝘅𝘁𝘂𝗿𝗲𝘀 𝗺𝗮𝗸𝗲 𝗳𝗶𝗿𝘀𝘁 𝘁𝗶𝗺𝗲 𝗲𝘃𝗲𝗿 𝗮𝘂𝘁𝗼𝗺𝗮𝘁𝗲𝗱 𝗽𝗮𝗿𝘁 𝗮𝗻𝗱 𝗳𝗶𝘅𝘁𝘂𝗿𝗲 𝗵𝗮𝗻𝗱𝗹𝗶𝗻𝗴 𝗽𝗿𝗼𝗰𝗲𝘀𝘀-𝗿𝗲𝗹𝗶𝗮𝗯𝗹𝗲 𝗽𝗼𝘀𝘀𝗶𝗯𝗹𝗲. 𝗚𝗿𝗲𝗮𝘁 𝘀𝗮𝘃𝗶𝗻𝗴𝘀 𝗶𝗻 𝘁𝗶𝗺𝗲, 𝗺𝗼𝗻𝗲𝘆 𝗮𝗻𝗱 𝗾𝘂𝗮𝗹𝗶𝘁𝘆 𝗮𝗿𝗲 𝗽𝗼𝘀𝘀𝗶𝗯𝗹𝗲 𝗰𝗼𝗺𝗽𝗮𝗿𝗲𝗱 𝘁𝗼 𝘀𝘁𝗲𝗲𝗹 𝗳𝗶𝘅𝘁𝘂𝗿𝗲𝘀.” The video shows some insights.
By Joerg Demmel June 4, 2025
At High Temperature Concept, we’re always striving for most effective and efficient CFC Fixtures and Racks for our customers. There are above all two main preconditions why we can suggest this. First, our founder Jorg Demmel is one of the Pioneers of CFC Fixtures and the only one with a PhD in this field. Furthermore, he and his team developed between 1995 and 2002 in Stuttgart a new generation of Fixtures: A new Technology by German engineers reshaping how parts are handled and treated in high temperature environments . Second, he decided partnering in the field of CFC Workpiece Carriers with Americarb, an US based CFC developer and manufacturer. Driven by the clear idea: Serving American heat treaters best with custom designed CFC Fixtures manufactured in the USA . The result: best-in-class CFC Fixtures and Racks with best Performance, Quality and Prize. Today Dr. Jorg Demmel likes to introduce the 10 Advantages of CFC Fixtures . His knowledge arose over now three decades serving for the industry leaders like Mercedes, Bosch, Rolls Royce or MP Materials, just mentioning a few. We recently came across an insightful presentation by Dr. Jorg Demmel explaining the remarkable benefits of CFC fixtures, and we’re excited to share these insights with you. Whether you’re in aerospace, automotive, or any industry reliant on heat treatment, understanding these advantages can save you time, energy, and money. Table of Contents 1. What Are CFC Fixtures? 2. The 10 Advantages of CFC Fixtures 3. How CFC Fixtures Improve Product Quality 4. Energy Efficiency and Cost Savings with CFC Fixtures 5. Why Choose CFC Fixtures for Your Heat Treatment Shop? 6. Frequently Asked Questions About CFC Fixtures What Are CFC Fixtures? Before diving into the benefits, let's briefly clarify what CFC fixtures are. These are specialized racks and fixtures designed for high-temperature heat treatment processes. Unlike traditional steel baskets, CFC fixtures are engineered to be lightweight, modular, and extremely durable — tailored to improve workflow and reduce operational costs. The 10 Advantages of CFC Fixtures Dr. Jorg Demmel highlighted the ten core benefits of using CFC fixtures in heat treatment applications. Here’s a closer look: 1. Five to 12 Times Lighter CFC fixtures drastically reduce the weight burden on your equipment and operators. Whether modular or monolithic, they are significantly lighter than conventional steel racks — making manual handling easier and opening the door to potential automation. 2. Uses Five Times Less Energy Because of their lightweight design and their increased strength at higher temperatures, CFC fixtures require far less energy during the heat treatment process. This translates to a major reduction in your facility’s energy consumption and costs. 3. Up to Two Times More Net Load Capacity You can load more parts per cycle thanks to the efficient design smaller volume and strength of CFC fixtures. This boosts your throughput without compromising safety or quality. 4. Up to 30% Less Processed Cycle Time Speed matters. CFC fixtures help shorten heat treatment cycles by improving heat transfer efficiency and minimizing downtime — allowing you to process more parts in less time. 5. Five Times Longer Life Cycle Durability is a key factor. These fixtures outlast traditional baskets, meaning fewer replacements, less downtime, and long-term savings. 6. Up to 90% Less Rework Thanks to superior design and material quality, parts handled in CFC fixtures require far less rework, reducing waste and improving overall productivity. 7. Up to 90% Less Product Distortion One of the biggest headaches in heat treatment is part distortion. CFC fixtures minimize this risk, ensuring your parts come out closer to their intended specifications. 8. Automation Friendly With manual handling minimized, CFC fixtures integrate seamlessly with automated systems, boosting consistency and safety. Reason why: CFC doesn’t change dimensions and form in technical vacuum and inert gas atmospheres. 9. Reduced Hard Machining Since the parts suffer less distortion and damage, hard machining steps after heat treatment can be significantly reduced. 10. Enhanced Quality Control CFC fixtures contribute to a more consistent and higher product quality, meeting the stringent demands of industries like aerospace and automotive. The scatter of the measured values for CHD, structure, hardness, etc. in one batch is by experience lower than in conventional steel fixtures. How CFC Fixtures Improve Product Quality When quality counts, the stability and precision of your fixtures are critical. CFC fixtures offer consistent support and spacing for parts during heat treatment, which drastically reduces distortion and defects. This means fewer rejected parts and higher satisfaction from your customers. Energy Efficiency and Cost Savings with CFC Fixtures Energy consumption is one of the highest costs in heat treatment operations. Thanks to their lightweight and thermally efficient design, CFC fixtures help reduce energy use by up to 80% compared to traditional fixtures. This efficiency, combined with longer fixture lifespan, means substantial savings for your shop year after year. Why Choose CFC Fixtures for Your Heat Treatment Shop? At High Temperature Concept, we believe in investing in technologies that deliver real-world benefits. CFC fixtures don’t just promise improved performance — they deliver measurable advantages, including: Lower operational costs Improved throughput Better product quality Reduced environmental impact Switching to CFC fixtures is an investment that pays off quickly and keeps giving back over the long haul. Frequently Asked Questions About CFC Fixtures What materials are CFC fixtures made from? CFC fixtures are crafted from high-quality Carbon Fiber Reinforced Carbon designed to withstand extreme temperatures and mechanical stresses, ensuring durability and reliability. Can CFC fixtures be customized for different parts? Absolutely! Their modular design allows easy customization to fit a wide variety of parts and applications, making them versatile for any heat treatment shop. How much energy can I expect to save? Typically, energy consumption drops by up to 80%, largely due to the reduced mass and improved heat transfer properties of the fixtures. Are CFC fixtures compatible with automation? Yes, their lightweight and standardized design makes them ideal for integration with automated handling systems. CFC is a unique material with a C.T.E. value around zero. The first material I know which allows easy and reliable automatic handling in heat treatment processes. Up to fully integrated material flow solutions between soft and hard machining. How do CFC fixtures reduce product distortion? By providing stable and uniform support during heat treatment, they minimize thermal stresses that cause part deformation. By providing stable and uniform support during heat treatment, they minimize thermal stresses that cause part deformation. The main secret is a design with reduces the fixture volume to a minimum and gives the products optimal chemical, thermal and mechanical conditions during heat treatment. At High Temperature Concept, we’re excited about how CFC fixtures can revolutionize heat treatment operations across industries. If you’re looking to save energy, improve product quality, and reduce cycle times, exploring CFC technology could be the next big step for your shop. Feel free to reach out or explore more at High Temperature Concept to learn how we can help you implement these cutting-edge solutions.
Vacuum Furnace Fixture and Rack
By Joerg Demmel May 14, 2025
Discover how CFC Vacuum Furnace Fixtures and Racks improve throughput, precision, and lifespan in industrial heat treatment. Lighter, stronger, and built for 2000°C+.
A foundry worker is quenching casts in an oil bath (Shutterstock)
By Joerg Demmel May 19, 2019
CFC Fixtures and Oil Quenching ? Graphite has an open porosity of about 5 to 20 % due to the production process. The open porosity is of particular importance for the use as a carrier or rack material in heat treatment processes because of mainly two reasons: first, there is a general influence on the thermal shock resistance: the higher the open porosity, the higher the thermal shock resistance because an open porous sample, e.g. at quenching inside cooled faster than a closed one, so the temperature gradient is flatter and therefore the tensions are lower. Second, there is the influence on all processes with fluid media, f. e. quenching or washing media, because of de-/absorption of the fluid by the material. The open porosity was measured for CFC samples using the water buoyancy method according to DIN 51918. The dimensions of the samples separated form a plate and removed from dust were approx. 100 x 50 x 5 mm. The results are shown here:
C.T.E. values of heat-resistant materials compared | Dr. Jorg Demmel
By Joerg Demmel April 20, 2019
Discover how CFC Fixtures and Racks can reduce product distortion in heat treatment. How is it possible? A low density and volume of CFC combined with high shape and dimension stability compared with conventional metal rack materials reduces the impact of the rack on the products and the product distortion.