March 29, 2017
Cold Hardening Phenol: The new all-rounder among binder systems
Faster and more efficient production of sand cores and molds
ExOne is constantly working on the development and improvement of its machines and binder systems. The ExOne development team has been testing the new binder CHP – cold hardening phenol - for several months. The CHP project manager, Dr. Martin Bednarz, explains the binder and its applications.
What is special about CHP?
The special aspects of CHP special can best be explained in comparison to our furan system. With the CHP binder it is possible to create moldings and cores with a higher heat resistance than those created using furan. In addition, the gas development during casting is considerably lower than what is found in furan parts and the resulting gas defects in the casting are significantly lower. The higher heat resistance also reduces the tendency to form sheet ribs in high-temperature casting.
What does that mean for the casting and complexity of the core?
Due to the higher cold and hot strength of CHP, even greater part complexity and delicate geometries can be realized. In fact, molds and cores printed with this binder are more suitable for iron and steel castings. CHP has the added benefit of being classified as safer to human health than furan. Odor issues that occur during printing, unpacking, and casting of furan molds and cores is significantly reduced when using CHP. This is especially important as workplace and environmental regulations become stricter.
And how do CHP printed cores behave when unpacking and cleaning?
Unlike Hot Hardening Phenol (HHP), no heat treatment before unpacking must be performed with the CHP process. Curing occurs at room temperature and typically, within a few hours. Cleaning the components is much simpler than with furan, since the sand barely adheres to the surface and diverts almost completely by itself. In order to reduce the residual moisture in the dried molds and cores, an application-specific heat treatment can be carried out after unpacking.
How have customers received and benefited from the developments so far with the Cold Hardening Phenol binder?
ExOne works very closely with its customers and always focuses its developments on the market. The positive results that we have already achieved with the CHP binder system have also already spread among our customers and interested parties. For example, our long-standing customer ACTech has already successfully integrated CHP with their S-Print in prototype production. Additionally, we have already sold four S-Max CHP sysetms, of which the first will be put into operation by our customer in March.
CHP advantages at a glance
+ Saves time: cores and molds can be taken directly from the Jobbox and cured separately in an oven or microwave
+ Easy finishing: no migration of the cores and molds with unprinted sand
+ All-rounder: combines the advantages of all other binders
+ Reduced environmental impact
+ Strength: higher cold and hot strength
+ Better surface: reduced formation of veining
+ Geometry: production of more complex cores and molds
What other strategies does ExOne plan for further developing Cold Hardening Phenolic binder?
With our CHP binder, we see many advantages for our customers and will therefore continue to develop the existing system. New material combinations with special sands are being qualified for this purpose. In addition, we are working on system performance and post-printing hardening times. We are excited to have CHP occupy a solid place next to our existing binder systems furan, silicate, and HHP. CHP and other future developments will continue to grow our product portfolio.