A product cannot be produced without a design. Machined components are designed on computer programs such as Autodesk Inventor, Solid Works and AutoCAD. A computer model is useful to engineers and designers, however lacks a lot of information required to actually produce a working part.
CAD models do not contain size tolerances, only absolute sizes. The problem with this is most components make up an assembly, that must fit together. Manufacturing processes have repeatability errors and accuracy requirements. Producing real parts from virtual models requires an engineering drawing to guide the machinist in the manufacturing process.
The more accurate a part must be requires more accurate machines, more stable and secure processes and more accurate inspection procedures. Therefor components that must be made to exacting standards are more expensive.
Once the machinist has received a fully dimensioned and toleranced drawing from the designer they must begin to plan all of the steps. Often called operations or “OP’s” these are the individual actions that will be taken to turn raw material into a finished product.
First the machinist must analyze the size, material and geometry of the part. All of these factors will determine what machines and tools must be utilized.
Sometimes shops do not have all of the equipment needed and specialized heat treating or finishing operations must be subcontracted to a third party supplier.
Pricing a manufactured part can become quite complex. Aside from labor, overhead and the cost of capital equipment, the main factors that affect price are: tool usage, fixture design and the time it will take to develop programs for the CNC machines.
There are many other variables that directly increase the price of manufactured goods:
Quantity or batch size
Quality documentation and inspection reports
Special or custom tools
Quoting systems range from scratch pad calculations to automated software programs that factor every last detail into a customer quote. Of course there is always a margin added to the cost of part to cover development time, scrap and profit allowance.
An honest and fair price often proves to be the best for both manufacturer, designer and the end user. If your customers have good business, you in turn will also. Understanding what is important to your customers is the key to meeting their needs and building long lasting partnerships. As Henry Ford said, “ a business that only makes money, is a bad one”
Receiving a purchase order.
Once a customer has worked with us to clarify their designs and any questions we have about their drawings, they must issue a purchase order or PO. The purchase order includes details about the number of each part they would like us to make, as well as delivery dates.
After an order is placed we must start to schedule the resources needed to produce the customers parts. Time at each required machine and process, including the time for materials and special tooling to arrive is juggled into our calendar. If we can not produce the product within the specified time period, we contact the purchaser and discuss possible changes to delivery dates. Transparency and honesty are very important at this stage, on time delivery is becoming more and more crucial in a lean supply chain system like most companies are now adopting.
Purchasing Materials and tools
As promptly as possible, once a PO has been received, the manufacturer starts to gather and schedule the resources needed to produce the parts. Material for the parts, any work holding fixtures and special tools are all ordered and linked to a work order in our system.
Every manufactured part in an organized shop has a lot of data associated with it that must be kept organized. Drawings and CAD files must be organized, as well as updated to ensure they meet the current revision a customer is ordering. Work instructions and programs, First article, in process and final inspection quality data and procedures for each part must also be organized and linked to the component. Even the physical fixtures, and special tools must be stored in an organized manner so that when the customer asks for another order, or records of parts made in the past.
A part is moved through the shop in as linear a fashion as possible, from one process to another and takes shape into a final product. Often after the machining process parts are still deburred by hand. The deburring job actually requires significant talent and experience to know the right process and tool for the job. The goal being to remove any sharp edges that are not suppose to be there, and make the part look great for the customer.
Inspection of the part throughout the process, as well as a final inspection ensures that it meets the customer requirements. There are many levels of inspection ranging from in-process only to full 100% inspection documented for each part, linked to a serial number and sent with the parts to the customer.
Parts are then thoroughly cleaned and protected to be delivered to customers. This may include processes such as ultrasonic or vapor degreasing, being packaged in oil or wax to prevent corrosion, and even custom cases or crates, depending on the location of the customer or end user.
After an order is delivered to a customer, it is important to ensure that your methods of manufacture, inspection and shipping align with the values of your customer. Sometimes you may be able to help the cost and the environment by reducing packaging, changing a process or even the design of a part to better meet your customers needs.
There is always room to improve your process as a manufacturer, and pass those savings along to a customer, the longer and more times a manufacturer produces a part, they will better understand the weak links in their processes. Only through continuous improvement, capital investment and staff training can a manufacturer remain financially and technologically competitive.