General Kitting versus Kitting Using Lean Thinking:
General Kitting is a natural, value-added process that is a part of many sortation and order fulfillment centers. In a production kitting operation, individually separate but related items are grouped, packaged, and supplied together as one unit. Kitting often includes processes such as invoicing, packing, sealing and labeling:
Warehouse kitting is the process of taking multiple SKUs and combining them in a package to create one new SKU. Many large companies build thousands of kits daily for retailers and multi-level marketers. A Warehouse Management System (WMS) accurately manages your inventory, as products morph from units to kits.
When you go out for bid on a kitting assembly you must:
- Have the bidder come into your facility to actually see the kitting operation
- Take a video of the kitting operation for all bidders
- Send samples of the kitting operation in bulk to the bidder and have them simulate the kitting assembly
- Create detailed assembly instructions for the bidders
- Give weekly, monthly and yearly forecasted quantities to the bidder
- Collaborate with the bidder once they are ready to quote in the spirit of cooperation
- If the forecast is too high and the actual quantities are lower the price will be increased
Applications for specified combinations of products to go into combo kits. Other customers want the capability for their operators to easily build combo kits whenever needed using scanners to set up the contents of the kits based on predefined needs.
- Here are some of the benefits of a production kitting solution:
- Fewer purchase orders and fewer stocked items
- Lower inventory carrying costs
- Faster assembly
- Fewer shipping mistakes
- Better and more economical packaging
- Reduced storage costs
- Custom kits for high-usage components
- Greater attention to critical parts availability
- Faster inventory turns
- Reduction or elimination of no longer stocked items
- Greater attention to critical parts availability
Is Kitting a Waste and should it be eliminated? In a Lean world, kitting is considered a waste. Following Toyota’s Lean thoughts of the past, we should provide component storage racks, replenished using Kanban (pull system) signals, alongside assembly lines and have operators pick parts to set up the job when needed. In addition to that value added work, operators will also be responsible for locating parts, performing part verification, setting parts on feeders and setting feeders on machine. This approach, although eliminating kitting as a waste, may create waste in the area that does much more damage to the company’s bottom line – assembly line throughput and process quality.
An attempt to eliminate kitting should not be undertaken without much consideration of how it may affect the overall process and assembly line efficiency. Furthermore, it has been recently reported that Toyota has started using kitting in some of their plants for high volume assembly operations Toyota has implemented a new kitting process, called Set Pallet System (SPS), in their new production facility in San Antonio that makes Tundra full-size pickup trucks. Previously, line-side storage racks were used by operators to pick parts. Operators would walk from their assembly station to each rack and pick parts to install. SPS introduces kitting personnel that receive a signal with a list of parts to be kitted, pick parts from storage racks, and then deliver pallets of parts to the assembly stations.
Assembly operators are not involved in the part picking process any longer. The advantage of this approach is more value added time by the operators, cleaner work areas with visual control, fewer part selection errors, and easier training of assembly operators. The disadvantage is increased manpower by adding kitting personnel. This approach is equivalent to the supplier-driven supermarket kitting for PCB assembly, as explained in the previous section.
Lean Kitting: The approach taken in the kitting process improvement project described in this paper can be summarized as follows:
Eliminate waste related to machine downtime caused by invalid kitting Kitting done right the first time
Eliminate waste in kitting: The priority is to eliminate waste on the assembly line by making sure machine downtime due to kitting problems does not happen. Next is to eliminate waste and make the kitting process as lean as possible. This Lean Kitting project was implemented at a large electronics contract manufacturer’s site. The project involved an assembly line that included a new Fuji NXT pick-and-place line. The NXT machine is based on a new concept of modular, scalable, and reconfigurable pick and place machines. This NXT machine had 10 modules. Thus, the same part number may occur on different modules as a result of placement sequence optimization and load balancing. In consultation with the plant management, the following goals were set:
Reduce kitting cycle time
Reduce number of partial material packages returned to stockroom
Eliminate the issue of insufficient quantity of material packages (reels) for parts split between different modules on NXT machine.
Eliminate the possibility of wrong components being kitted by implementing electrical component test and component verification Kit quantities per part number calculated by the ERP system do not take into account that a part could be split between a number of modules during machine optimization. For example, if the kit requirement for a part that is split between two modules on a machine is 4500, the stockroom may find a reel with 5000 parts and kit it for that part, which will cover the Bill of Material (BOM) quantity plus estimated attrition. The single reel will be sent to off-line setup and it will need to be split, or another reel ordered, which delays off line and adds manpower related costs. Another case is when the stockroom does kit two reels, with quantities of 4000 and 1000. Let us assume that the quantity placed from the first module is 2800 and from second module is 1700. The off line setup personnel will have two reels to prepare for the run and production can be started, but there is not enough quantity on the second reel and the machine will stop until a new reel is provided, adding to the machine downtime. In this project, all activities that lead to delivering the kit to the assembly line, were considered to be part of kitting, including:
Pulling enough quantity to place each part (including attrition) Determining which reel will be used first
Verification of component electrical characteristics
Verification of component feeder type, feeder rotation, and height verification Lead free compliancy
Setup verification: Even though kitting can also include delivering the tooling kit to the line, it was considered out of the scope of this project.