Assigning each piece of material a unique serial and logging all events about the material as it moves through the factory provides enormous benefits to quality control and operations. During operation, unique serials and barcode readers help the operator and the automation track parts at in-process transfer stands, conveyors, or moving between separate cells. At the inspection stand, the operator can view the history of the material being tested. Multiple failed inspections can be analyzed to find similarities (such as failures only appearing on a single pallet-machine combination). Once a part fails inspection, the operator can query for serials that ran on the same machine at the same time. Each piece of material has a record of which tools were used.
FMS Insight automatically assigns a unique serial to each piece of material and tracks that material while it is controlled by automation or robots. FMS Insight also assists the operators with barcode scanning the parts as they enter and leave the automation. To do so, the unique serial must be printed on the part. Because there are so many different ways, FMS Insight provides a plugin system; the plugin is customized and can be adapted to any situation. Typically, we recommend one of two possible approaches: a special tool inside the machine or a sticker label printer at the load station.
One option is to use a special tool to scribe a QR or Data Matrix barcode onto the part inside the machine. (We have tool recommendations or can work with your own custom tool.) In this case, the custom plugin to FMS Insight will watch the pallets and when a pallet is rotated into the machine, the plugin will generate a unique subprogram containing the G-code to perform the scribing. The plugin can be customized to insert other data in addition to the unique serial into the QR-code: the part name, date and time, machine, pallet, etc.
The second option is to use a label printer such as a Zebra printer at the load station. In this case, the custom plugin to FMS Insight will watch the pallets and when a pallet is moved to the load station, the plugin will send the barcode to the label printer. As part of the load/unload process, the operator will attach the label to the part.
The goal of our engineering design is to keep the machines busy so that machines are always the bottleneck of the overall part flow. When designing the part flow, we should strive to ensure that unavailability of raw material never starves the machines.
The easiest way to keep the machines busy is to let the machine operation drive the replacement of raw material in a pull-based lean technique. In this scenario, the scheduling and ordering assume that raw material is always available and pick a daily schedule which best keeps the machines busy. At the load station, there are several baskets or containers of castings. When a casting basket or container is nearly empty, a request for more castings is made and the basket is refilled. In this scheme, the castings are purchased/acquired by a signal generated when the casting basket is nearly empty.
Sometimes, there are a large number of infrequently used castings and keeping a stockpile of castings in inventory is costly. In this case, the availability of castings must become part of the scheduling, ordering, and cell control. This complicates the operation because we must ensure that the machines stay busy, deal properly with extra castings needed because of scrapped parts, and develop custom ERP and data control processes. FMS Insight and OrderLink assist with managing the availability of castings. In this scheme, the ERP system will issue purchase orders for castings as part of the overall ordering process. The available castings on the shop floor are entered into FMS Insight. First, FMS Insight will inform the cell controller which castings are available and only bring pallets to the load station if a casting is available. Secondly, OrderLink will take into account the available castings during its optimization and attempt to keep the machines busy using only the available castings.
A major benefit of automation is that it is part-focused instead of order-focused. Dozens of orders and parts can be machined simultaneously with the cart, pallets, and cell controller keeping track of each individual part. Once parts leave automation, it is much harder for humans to track each individual part. Indeed, one of the main tenants of lean manufacturing is the kanban: a container or basket of parts that move together and no part moves without being in a kanban.
We suggest that once parts leave the automation, they are grouped into a kanban and move together throughout the remainder of the factory. Each workorder should have quantities that match with the container or group of parts that will become the output of the cell. (Since workorders and bookings are separated, it is possible to split a single large customer booking into multiple workorders if needed.) An operator should group the completed parts into baskets or containers based on the workorders. Once the required quantity for a workorder is reached, the entire basket is then sent out of the cell. We typically see two possible strategies based on where the final wash happens.
If the parts are washed outside the automation but immediately after they are completed, we typically suggest that the parts move individually from the load/unload station to the wash stand, still viewing the wash stand as internal to the cell. In this scenario, after unloading the part, the operator moves each completed part to the inbound queue for the wash stand. The wash operator performs the wash and once the wash is complete assigns the part to a workorder by scanning its barcode. To do so, at the outbound of the wash stand, there are several baskets or containers or just taped squares on the floor. Each basket/pallet/location is temporarily assigned to a workorder. When the wash completes, the operator scans the barcode on the part into FMS Insight, which then displays the list of unfilled workorders. The operator assigns the serial to a specific workorder and then places the washed part into the associated container. Once the workorder is complete, the basket is then sent out of the cell to the rest of the factory.
Alternatively, if parts are not immediately washed after leaving the automation, we suggest that the workorder filling into baskets/containers/floor locations happens at the load station. The load/unload operator can enter into FMS Insight a workorder and directly place the completed part into the associated basket/location on unload.
Parts signaled for inspection
If all parts go through an inspection such as a CMM machine, we recommend that this happens after the parts are filled into a basket/container/kanban. The kanban/workorder group will move together to the CMM machine, be inspected, and be retained in their kanban. This eases the part flow and human part tracking, since the parts move together in their completed workorder.
If only a subset of parts are periodically inspected, a decision must be made on whether the inspection happens before or after workorder filling. One option is to perform the inspection before workorder filling. In this case, at the unload station, FMS Insight will display that a part has been signaled for inspection and the unload operator will move the part to the inspection stand to await the inspection operator. Once inspection is completed (and successful), the inspection operator returns the part to the normal part flow. This works particularly well if workorder filling happens at the wash stand; during unload, the operator either moves each part to the inspection stand if it is signaled or moves it directly to the wash stand if no inspections are signaled. Once inspected and washed, the parts are filled into workorders.
Alternatively, if the parts are filled into workorders at the load/unload station, the entire kanban/basket should move together to the inspection stand even if only a single or a few parts in the group are signaled. In this case, during unload FMS Insight will display that a part being unloaded is signaled for inspection and the operator should visually mark the part, perhaps with a small piece of red tape. The part is then assigned to a workorder and placed into a basket where it waits and does not immediately travel to the inspection stand. Once the workorder is filled, the entire basket/container is sent to the inspection stand. The inspection operator sees the part marked with red tape, scans its barcode into FMS Insight to bring up data on the specific material, performs the inspection, and returns the part to the basket/container (of course, only if the inspection is successful). This allows the kanban to be kept together for easy tracking.
Assigning a unique serial and printing it onto a barcode on the part eases operations and tracking as parts move from automated to manual handling. FMS Insight can use handheld barcode scanners to help track raw material and castings, in-process material on transfer stands, and completed material being inspected and/or washed. FMS Insight is flexible enough to adapt to any part flow, allowing the overall system to be designed so that the machines stay the bottleneck.