Determining the cost of fabrication can feel extremely tricky due to all the different factors. While the factors affecting costs are varied, there are some major contributors that can be considered for creating reasonable estimates. We are going to leave out the research and development costs for the time being and focus on the cost of physically fabricating and producing your part.
Material
The material that you are using to manufacture your part(s) is one of the biggest factors in determining the costs of your process. Some materials such as engineering plastics tend to be less expensive than other materials such as steel. Different metals are also going to have different costs as well. The thickness of the material will play apart directly in the cost of the material itself, but also in labor. It is important to pick the material that has properties that you need for your project, but if multiple materials could meet your requirements, costs are often a determining factor. The cost of a metallic material is often driven by external market factors, but usually, these are not extremely volatile.
Labor
When it comes to labor, you have to consider both human and mechanical labor in producing the part. Often times, when we think about labor, we consider the amount of human labor that is required. This is a factor when it comes to manufacturing as individuals will be working throughout your manufacturing process. Between loading materials, moving pieces between machines, inspecting, etc. However, we also have to consider the amount of time that a part is in process in/on a machine. Machine time is a major factor in determining your cost. Your part is likely going to spend more time in the “hands” of the machine than a person, thus it cannot be forgotten.
There are some factors that may affect machine time that are controllable such as material (some materials require more time to process safely) and design specifications. In addition, thicker or more durable materials will require more machine to process the part.
Complexity
The complexity of a part can also be a factor in the cost of manufacturing a part. A design that is more simple and requiring fewer cuts, mills, bends, etc. is going to cost the least. A part that requires many cuts or several bends is going to cost more time on each machine and moving from machine to the next. These types of projects may cost more in the prototyping and design phases as well. Greater complexity simply translates to greater costs.
Along with complexity, we also consider accuracy. If accuracy is not a major factor, machining can be done more quickly; however, usually parts are going to require more accuracy in this day and age. When greater accuracy is needed, the amount of time your part takes to process is going to increase, and we all know time is money.
Finishing and Quantity
A part that needs no finishing would be complete after coming off the manufacturing machine(s). The reality is that most parts are going to require at least smoothing or sanding of edges. Most likely, other finishing from assembly to polishing and painting to marking is going to be needed and going to add to the costs. These finishes are usually necessary rather than optional, but it will be dependent upon your needs and wants.
When it comes to quantity, there are two things to think about. Obviously, the more copies you reproduce the more the total cost will increase. However, with each additional reproduction, the average cost per item is going to decrease. Due to a number of different factors that then can include getting multiple parts from a single piece of material and not having to set a machine up again for producing multiple copies (thus reducing some labor time), the cost of producing each successive copy is less than the first. This also allows the manufacturing facility to create a workflow that becomes more efficient.
There are other factors that can still affect the cost of fabrication. There are entire chapters in textbooks dedicated to the costs of fabrication. It can be daunting make decisions and determine the costs for your project. It is always best to consult with your professional fabricators at Engineered Mechanical Systems to help with estimates and options to save you some stress and time.