Automated and semi-automated alternatives to manual cut listing depend on the nature of your products. The majority of wood products can be divided into units. Each separate box in kitchen cabinets can time-consuming as a unit. Doors and windows are usually discreet units. There will, of course, be miscellaneous parts that won’t be considered units and these will have to be cut listed manually.
The feasibility of each alternative method as compared to manual cut listing depends on how many times a “unit type” will be used. A unit type is defined by the relationship of the overall unit to the individual parts that comprise that unit. In other words, units of the same type are constructed identically. Therefore, the relationship between the overall unit size and the individual part quantities, sizes, and orientation is the same. So the overall unit size will be used to determine the size of each and every part. Mathematical formulas can be created to calculate part quantities and sizes based on the overall unit width, height, and depth. An assumption here is that the units are basically rectilinear, although the principles can be used for other unit types as well.
The first level of automation for the task of cut listing is to create formulas, usually in a spreadsheet, that will be used to calculate part quantities and sizes. A simple example is a cabinet box where the bottom panel fits between and butts up to the side panels. If the thickness of the side panels is ¾”, then the length of the bottom panel equals the unit width minus 1 ½”. If the side panels were to sit on top of the bottom panel, the unit type would be different.
Creating formulas that will be used to generate a cut list becomes feasible only when several units of the same type will be needed. Let’s say we have a standard construction for a double-hung window but we need this type of window to fit into several differently sized openings. Once we have the formulas established, all we have to do is enter the number of units we need of each particular size along with the overall unit width, height, and depth. All of the part quantities and sizes will be calculated automatically. Computer magic is a beautiful thing.
So, let’s look at both the advantages and limitations of using formulas for cut lists:
Advantages of using formulas
- Once tested, they can be relied on to calculate correct quantities and sizes of parts
- Repetitious calculating is eliminated, so errors are reduced
- They can be used over and over, greatly reducing the time needed to produce cut lists
- They can be modified to be used on different unit types
Limitations of using formulas
- They require more time and effort to create than calculating cut lists manually
- Therefore, they’re not practical for one-off units
- Due to their abstract nature, not everyone has the ability to create formulas efficiently
- Since they aren’t linked to the drawings, care must be taken to ensure that the correct unit type is identified so that the correct formulas are applied.
The next level of automation becomes feasible when a company has a unit type that will be produced many times in various sizes. This method links the cut list to the drawing itself. It requires the use of a parametric 3-D modeling program (also known as an engineering program) such as Solid Edge, Solid Works, Inventor, etc.
When a 3-D model is created parametrically in one of these programs, you get much more than just the model itself. Building a model parametrically means creating parameters (variables) that define the size of the unit. The model you create for each unit type is called a prototype. Once it’s created, the process of creating units of this type in various sizes becomes computer magic on steroids. To create the model for a new unit in a different size, all you need to do is change one or more of the parameters that defines the unit width, height, or depth. The model is automatically re-created in the new size, along with any 2-D layouts (including updated dimensions) that you set up when you made the prototype. The cut list, controlled by the same parameters, is not only updated but can be automatically exported to a spreadsheet.
There is, of course, a downside. Creating a prototype is a time consuming proposition. It pays for itself only when substantial quantities of a particular unit type are required. Also, some of these programs are difficult to use and some lack efficiency. I’ve done considerable research on several of these programs and have found Solid Edge to be the most efficient for making prototypes of wood products.
Another advantage of using both formulas and parametric 3-D modeling programs is that once you’ve created a prototype for one particular unit type, you can use that prototype as a starting point to create a new prototype for a similar unit type. The more similar the unit types are to each other, the less time it takes to create the new one. Often, the time required is only a small fraction of the time it took to create the first one.
The idea of using parametrics for designing wood products has been taken a step further. When many woodworking companies produce virtually the same products, it becomes practical for an enterprising computer programmer to create prototypes of these products and use them as the basis of a software program. Companies like Cabinet Vision, 2020, KCD Software, and Mirovellum have done this for the kitchen cabinet industry.
They make it easy to specify the details how you prefer to construct cabinets and then select unit types from a series of pictures. Many have add-on modules that integrate not only cut lists, but optimizers, labeling software, accounting software, etc.
They work well for kitchen cabinets but not as well when products deviate too much from typical cabinets; and they are expensive.
For small to mid-sized custom woodworking companies, cut listing is a time-consuming but essential part of producing wood products. Hopefully, this article has helped you to evaluate how you do this in your company in order to ensure that it’s being done as efficiently as possible.