RFID technology is a communications system for no-bake molding lines, with each core or mold box tagged with identification data, and a wireless reader that tracks each tag and associates the tagged box with related data. The data may include mixer run time required to face and fill, the type of sand or blend used, resin percentage, resin ratio, catalyst percentage, dry additive percentage, compaction table vibration intensity and duration required.
RFID is an automatic identification method, relying on storing and retrieving data using radio-frequency identification tags. At first, RFID technology was confined to package tracking and inventory control, but it has exploded into manufacturing — and not just for warehousing and supply-chain management. It has moved from tracking of finished parts to part production because it reduces operator errors, reduces overall labor, and increases jobbing productivity.
Similar in concept to barcodes, RFID technology has the distinct advantage of being completely programmable (read/write), does not require line-of-sight reading, and can be read at much greater distances than bar code scanning.
When applied across the plant floor, RFID deliver substantial labor savings, enhancing quality control and production efficiencies, giving plant and purchasing management better data to manage production and raw materials inventory. Because RFID systems can be added easily into an existing infrastructure, foundries of all sizes can benefit.
No Bake Molding
RFID technology has a very clear application in no-bake molding. The communications system consists of two components:
1. RFID Tags (small electronic devices that are attached to a core or mold box). Each tag has a unique identifier and memory to store additional data such as recipe numbers.
2. RFID Readers (devices that wirelessly communicate with the RFID tags) identify the box that the tag is attached to, and then associates the tagged box with related data such as mixer run time required to face and fill, type of sand or blend used, resin percentage, resin ratio, catalyst percentage, dry additive percentage, compaction table vibration intensity and duration required.
Both the tag and the radio are two-way radios. The reader interfaces with a PLC to transfer the data obtained from the tag to allow the PLC to set the mixer and conveyor/carousel parameters.
The recipe number and settings are entered into the RFID tag via a touch-screen on the mixer control panel or another PLC. The RFID tag, which mounts on the box, is programmed with a specific recipe number. When it is in range of the reader antenna, the parameters of the recipe number (resin %, ratio, etc.) are entered into the system PLC. The tag can be re-programmed any time and the ability to change a recipe number can be password protected. Additional recipe numbers with the associated control parameters can be entered into the PLC at any time.
The RFID System permits a specific formulation for each core or mold, so the foundry can reduce chemical usage, minimize gas evolution, ease knock-out and reclamation where possible, and increase the chemical percentage where needed for more strength. It can also minimize waste sand by controlling the mixer run time to that needed for a specific box.
After programming, the RFID tag is added to the mold box to identify itself to the mixer. Programming can be performed either at the production line or by downloading the settings from the company Ethernet.
At the start of the molding process, the cleaned box is ready to be filled with all necessary loose pieces, reinforcing rods, insulating sleeves, filters, etc. As the box flows past the RFID reader, the system reads the information on the tag and sends the information to the operating system. This read function can be automatic or the operator can perform it with a hand held reader. Depending on the style of the tag, it can hold different amounts of data, but generally it is simpler and the tag is less expensive to store only the pattern or job number on the tag.
Once the box is in the correct position, the operator starts the cycle. At this point the operator is no longer needed for any decisions as to the different settings of mixer run time, resin level, powder additions, etc. He needs only to move the sand to the correct part of the box as it is discharged to be sure the pattern is covered with the correct recipe. No operators is needed if the mixer is equipped with an automatic fill pattern mechanism on the mixer discharge, with an auto strike-off station (after the fill station.) Both of these functions are easy to integrate into the recipe number.
Each system is custom designed, but generally have the following data points:
- Mixer run time – with the potential for different sand flow rates
- Resin level to start & backup – and when to change
- Powder additions level – when to start and stop
- When to start the compaction table cycle – with force output & vibration duration specifications
Once the box is filled and compacted, it needs only to be struck-off and sent to the automatic rollover / draw machine. The overall operating system then either sends the box back to be refilled or to a different location to be removed from the line.
Since the system knows the amount of binder going through each pump and consequently the sand mixture, the amount of sand and binder being used is known. This allows purchasing managers to be sure the correct and lowest levels of consumables (binder, sand, sleeves, filters, etc.) are in stock since the usage can be tracked by the minute on the PLC or Ethernet. This system can be used to record the consumption of raw materials and track the number of specific cores or molds made per hour, per shift, or in any other time frame desired.
The same process can be used in the core room where racks of cores can have a RFID tag affixed and read when in position at the molding line. RFID tags can also be applied to the core boxes to identify themselves to the core blower. This easily allows you to keep the operators working while letting the RFID system change settings between different boxes. Programming of the blow pressure allows fine-tuning of each core.
Effective deployment of RFID quickly provides accurate data that exceeds that of bar coding or manual processes. RFID has a positive impact on jobbing operations with high numbers of changeovers as well as high-speed operations to increase speed, reduce downtime, increase accuracy, and provide accurate data to managers.
Jack Palmer is the President of Palmer Manufacturing & Supply Inc. Visit www.palmermfg.com