In October, Cutter Shea, sales engineer for Faro, talked about the bill of materials in relation to BIM in his webinar You’ve Skimmed the BOM, Now Scan for BIM.
It seems like an appropriate next step to discuss just what a bill of materials is and how it functions. For many who have not spent a large part of their career in manufacturing, a bill of materials (BOM) may not be a familiar tool. The fact is, we use them every day and probably don’t think about it. We certainly don’t say before we go to the grocery store, “I need to put together a BOM before I go.”
As the name implies, the BOM is a list of the materials needed for a particular project or process. Let’s take a look at a BOM for a very simple product – a lamp. We need the following:
- 1 cord assembly
- 1 base assembly
- 1 stem assembly
- 1 bulb assembly
- 1 lamp shade support
- 1 lamp shade.
That’s our bill of materials, but it also contains a number of sub-bills of materials for each “assembly.” The electrical cord needs to be specified as to color and length, and it needs the appropriate plug. The plug could vary depending on where the lamp will be sold – the U.S., Europe, the U.K. Similarly, the stem assembly may consist of a threaded tube and a decorative sleeve it will be inserted into. Then there are nuts and washers to secure the parts and also to connect and secure the base and bulb assembly. You can see where this is going. By the time we are assembling our lamp, the product we thought of as having six parts may have 20 or more pieces – from a small set screw to the lamp shade.
Every surveyor who goes out to the field to do a job uses at least an informal bill of materials to prepare for the job. You’ll check the truck to make sure you have stakes, flags, survey washers, hammers, shovels, machetes, tripods, etc. You may not count out an exact number of stakes or washers, but you’ll look at the bin and estimate whether you have enough, and you’ll throw in another handful if you think you might be short. You’ll want to make sure you have all of your basic tools, and then you’ll think about the specifics of this job – rural farmland – better make sure there are at least a couple of machetes and an ax in the truck.
The bill of materials doesn’t actually stop here. There’s an apocryphal story about a manufacturing executive touring a plant. He sees a machine sitting idle and demands, “We spent $30,000 for that machine, why is it sitting idle, it should be producing parts.” The plant manager tries to tell him calmly that there is currently no need for the parts the machine makes and it is more cost effective to leave it idle than to produce excess parts that aren’t needed.
So, there’s another angle for the BOM – resources. For the manufacturer, this includes time on a particular machine tool and the operator and instructions as well as the raw materials for the parts to be produced. For surveyors, some of the resources are wrapped up with the tools. For the data collection on the job, you might bring along a tablet or computer with mass storage or a connection to cloud storage services. Those are less tangible resources, but they are part of the BOM. So is the knowledge and skill of the crew members. You wouldn’t send a crew into the field with a scanner that no one on the crew has been trained to use. So, when you are putting together your crew, you are also mentally ticking off a skill set BOM along with the physical tools and other resources the job demands.
The BOM is a good place to start the conversation about improving processes using manufacturing disciplines. Keep the “resources” attitude in mind, because from here, one of the next steps is to start assembling information about what resources are needed – including time.
To view Cutter Shea’s webinar, go to: https://www.pobonline.com/articles/101133-youve-skimmed-the-bom-now-scan-for-bim