Loose debris blowing around your furnace during backfill and/or pump down. Burning your parts and damaging your furnace. Broken thermocouples, eutectic reactions and hot zone damage.
These may sound like descriptions from a heat treatment horror novel, but they are all real possibilities that can occur over time if you don’t perform preliminary checks and take proper care of your heat-treating system. This includes ensuring your furnace is functioning correctly and that your load properly enters and exits the furnace.
Checking Equipment and Surrounding Area
There are quite a few items that should be checked before loading parts (as well as on a regular basis). Below are several recommended steps, many of which are also part of our preventative maintenance checklists:
- Inspect the furnace interior and hot zone for disc oloration, loose dirt and foreign matter
- Ensure the door seal and matted surface are clean and free of debris
- Check the elements, insulators, hearth and other components for looseness, cracks or any possible signs that could cause problems or contamination
- Inspect the molybdenum or ceramic rods located on the hearth for signs of chipping, cracking or distortion
- Inspect the control and overtemperature thermocouples (TCs) for signs of damage or heavy contamination
- Check all of the electrical equipment and controls to verify they are operating correctly
- Review the prior cycle for any incidents, alarms or occurrences; rectify causes if found
- Conduct a visual walkaround of the furnace to check for any leaks
Keep in mind that the workspace around the vacuum furnace should also be inspected. If you’re using a lift truck to load the furnace, the floor must be smooth and free of debris. If this is not done properly, the load may suddenly bounce during the loading process and could result in damage to the heating elements or TCs. Additionally, if the load does not go smoothly into the hot zone, parts may move or fall off, causing damage to the load and your furnace.
Step 1: Carefully place the workload on the center of the hearth (front-to-back and side-to-side). Make sure it is stable and no part of the load is close to or touching the heating elements. This can create arcing and cause major damage to your hot zone and parts.
Tip: Once the load is in place, mark the hearth posts with a hacksaw to quickly find the front and back measurements each time.
Step 2: If work TCs are required, plug them into the jack panel and bundle the wires to prevent them from contacting the heating elements.
Step 3: Check to make sure TCs are displaying the correct value on the HMI screen before closing the door.
Once you open the door to remove the load, you should perform the above steps in reverse order. As you prepare to remove the load, you should remove any TCs that interfere with the load, remove the TC plugs from the jack panel and inspect the fork truck area for debris. Once you complete those steps, you can then remove the load.
As you look for ways to prevent your equipment and production from turning into a horror novel, make sure to follow these steps and best practices. Not only does proper loading and unloading of the furnace help maintain the life span of your equipment for years to come, but it can also save you from unplanned downtime and lost profits that come from a damaged load or hot zone contamination.
Have questions about loading or unloading your parts? We’re here to provide support. Simply call our Aftermarket Support Helpline at 1-844-Go-Ipsen (Toll Free: 1-844-464-7736; International: +1-815-332-2530) or fill out our Ask an Expert form.