Eric Hill, Plataine
Customer demand for greater variety and shorter delivery times coupled with intense globalization have pushed upholstery manufacturing to seek new ways to optimize production. The shift from traditional stick-built frames to plywood engineered frames and CNC cutters has been one of the most fundamental changes the industry has made to address these new economic realities. With new materials and technologies in place, new methods are required, including a fresh mindset when it comes to frame design.
1. Design with structural strength in mind
The #1 rule every frame designer must to keep in mind is making all parts support each other. The basic idea is simple; you can look at it as the tent pole effect. A tent pole is weak without the guy wires in place to support each other. The same goes for an engineered frame; its strength comes from all the pieces being locked together to support each other.
All joints should be attached to each other using either staples, nails, screws, or any other fastening device in a bidirectional pattern. However, a strong frame design should never let a piece just but up to the connecting piece and depending on fasteners to hold it in place. To ensure the structural strength of your frame, every piece should either intersect or interlock with its connecting pieces.
Using a 3D design software package allows you to design these parts to create a more structurally sound frame. It can also help you reduce the cost of material and enhance the look of the piece. Using foam and other filler material in an upholstered piece carries a significant cost. Use the software’s advanced design capabilities to shape the piece instead of filling it out with filler material. This will not only reduce the cost but will also guarantee consistency in how the piece looks no matter which upholsterer built it.
2. Utilize the full potential of your CNC
Frame designs come in many forms, from a detailed drawing by a designer to a napkin sketched over lunch. Upholstery manufacturers transitioning from traditional stick-built frames to engineered frames are converting their existing designs to electronic formats that can be translated into the code fed into their CNC machines. However, by doing so, they fail to take advantage of the opportunities offered by the CNC machine.
Traditional frame designs were constricted by the limitations of the material and the tools used for frame construction. With CNC machines, the old saying “you can draw anything but you can’t make what you draw” no longer holds; a CNC machine can cut almost any shape imaginable.
Rather than mimicking the old frame design, 3D design software enables you to construct a frame that takes advantage of new possibilities offered by CNC machines. It allows you to design interlocking parts and visualize structural problems before the frame is cut and assembled, things that were just not possible or practical using hand-drawn design methods and traditional cutting tools.
3. Simplify designs for your CNC
With 3D design software on your desktop and a CNC cutter on the shop floor, you can make these frame parts almost any shape and size you can imagine. But that doesn’t necessarily mean you should. CNC machine time is a valuable resource that should be carefully utilized. Even though a CNC cutter is much faster and less labor intensive than the old ways of cutting wood, making compound cuts can easily double or triple machine cycle time. A good designer will take this into consideration and keep the frame design as simple as possible.
For example, in first glance a part may look like it could only be cut using an angled or miter cut. By carefully examining the surrounding pieces, you may find a way to change the design of the part and end up with a more simplistic frame utilizing through cuts that take less machine time.
4. Choose the right material for your product
What material should I use? This question is commonly brought up in every upholstery manufacturing environment. Attempting to keep the cost of material down may lead a company to engage in frequent material changes. While many parts in a frame can be made from a less structurally sound material, others cannot. For instance, a rail supporting the weight of a person should always be made of solid wood plywood rather than OSB or some other particle board.
In many cases, it is more cost effective and logistically simpler to use a single, more expensive material and avoid mixing materials altogether. Using a number of different materials will force the CNC operator to stop the machine and slowdown the process. The loss of machine productivity and the increase in labor involved with this extensive material handling may add up to increase your total cost of production beyond the anticipated savings.
5. Make design work for your assembly
Keep in mind that your frame design dictates the flow of the piece through the plant floor. Designing a frame with many small pieces may produce greater material yield, helping keep cost down. At the same time, using fewer parts will increase productivity and reduce labor requirements throughout the plant. This is a tradeoff that you have to be mindful of and balance based on your own company’s cost parameters and goals.
