Today’s modern foundry is under increasing pressure to reduce raw material consumption, minimise overhead costs but still continue to improve the quality of its castings. This has become even harder with rising costs of raw materials and the difficulty in finding skilled, motivated workers.
Omega Foundry Machinery Ltd has seen the need to de-skill the no-bake moulding area and mechanise as much as possible, thereby reducing waste, eliminating human error and maintaining a consistency of quality with full traceability. With this in mind, Omega developed the unique IRIS system, Chris Wilding of Omega reports.
IRIS (intelligent radio identification system) consists of three main components - the RFI (radio frequency identification) tag itself, the antenna and the HMI interface with industrial PC.
The RFI tag is a relatively low cost and durable component that can be re-written many times (fig.1). The small size means that it can be installed into the pattern with relative ease and convenience. The short-range antenna is usually sited at the mixing station close to the compaction table and protected by a Perspex case (fig.2). Finally, the HMI interface with industrial PC is the heart of the system that stores the data (recipe) to be used by each tag. The HMI is usually located in the main plant control panel, away from the immediate moulding area. The HMI is also the means through which the operator can read or write information to the tag or recipe. Production data can also be obtained directly through the interface itself.
Each pattern will have an RFI tag fitted; the tag is usually attached to the wooden pattern (or outside at the base of the pattern if a metal flask is used). The pattern, with a new tag installed, is then placed on the compaction table so that the antenna can communicate with the tag and the relevant recipe can be loaded. The operator will then set the recipe parameters via the touch screen interface; the typical recipe parameters are as follows:
1. Auto Mould Fill - for larger moulds an articulated mixer can be trained by the system to follow an automatic route when delivering sand to the mould.
2. Fill Time - the time that the mixer will deliver mixed sand into the pattern, (usually determined by trial and error to give exactly the correct amount of sand).
3. Run to Pause - the time at which the mixer will pause to enable the operator to place chills or loose pieces (optional).
4. Resin Addition - as a percentage.
5. Sand Type - new, reclaim or blended sand (or other types such as chromite).
6. Set Time - catalyst or hardener addition as a percentage.
7. Compaction Table Lift Time - duration of vibration.
8. Compaction Table Frequency - vibrator motor running frequency to determine amplitude.
9. Tag ID - a unique number or name for the tag that relates to the mould for identification purposes.
Once the relevant data has been added, the operator presses the ‘write’ button and the tag ID and recipe are connected. This operation need not be carried out again unless any modification is required for the recipe.
The next time that the pattern comes to the compaction table, the operator presses a start button, the antenna reads the tag ID and relates that number to the relevant recipe stored in the central PC. The mixer then starts automatically and together with the compaction table, delivers the exact sand mix recipe to the pattern at the exact frequency and time of vibration. No sand is wasted and the operator simply has to manually strickle to smooth the back of the mould (or this can also be done automatically when an auto-strickle machine is employed).
IRIS also has the facility to display a job card on the main screen, which will show a picture of how the pattern should look - with chills or loose pieces shown in the correct positions (fig 3). This is particularly useful when inexperienced operators are running the moulding loop.
Each consecutive pattern brought to the mixing station by the moulding line will be automatically recognised by its unique tag ID, filled to the exact recipe, compacted and logged in the system with minimal operator involvement.
It is also important to note that the antenna will not read a tag through a metallic flask, so in the case of metal flasks, a wooden block with the tag inserted can be attached to the edge of the pattern plate.
Taking RFI further
There are many possibilities to utilise this technology still further. Not only in moulding but also core making. The RFI tag can be inserted into any wooden core box or wooden backing plate, the antenna installed into the core shooter and a unique recipe given to every tag. The recipe would consist of core box position within the clamping system for auto clamping, gassing time/pressure and purging time/pressure. Also the number of cores produced is logged in the system.
The facility to network the RFI system on each individual mixer and core shooter to the main production office server is also possible. The data logging software is loaded onto the server and onto the production supervisor’s computer, this enables the supervisor to access real-time information from his or her personal computer (pc) giving details of the current mould or core being made, total production days to date and previous days, weeks or months of stored production data (fig.4). So not only are the numbers of moulds and cores made logged, but due to the detailed recipe information it is also possible to calculate the total volume of raw materials used on each mould or core, the cost of each individual mould or core and even the cost of each individual casting (fig.5). Of course, in this case there is a requirement for the foundry to enter into the system details of raw material costs, manpower and various other overhead costs.
All production data can be stored on a hard drive or CD in either Excel, Microsoft Word or pdf format for storage and future access, giving total traceability for each mould and core made. Patterns with tags fitted can be stored for long periods of time without use, brought back into production and without any further calculations be put straight back onto the line as the recipe is stored in the HMI and the antenna will immediately recognise the tag ID.
Foundries should embrace this kind of proven technology to give them the competitive edge they need in the castings market as well as ease the workload on already overstretched foundry personnel.
Contact: Chris Wilding, Omega Foundry Machinery Ltd, Tel: +44 (0) 1733 232231, email: email@example.com web: www.ofml.net
For copies of the figures that accompany this article refer to the full printed article in the October issue of Foundry Trade Journal