Are “screw machine products” primarily screws?
Not at all. The term “screw machine product” is really a misnomer today. One hundred years ago, when the term was first applied to a mechanically automated lathe, the primary use for the machine was for making screws. Today your hardware store variety “screw” is made by the cold heading process, which is less precise but provides lower cost per piece. Screw machines are used for an endless variety of products turned from bar stock to high tolerances, far beyond the simple nuts and bolts of the past.
What encompasses CNC (Computer Numerical Control) turned products and screw machine product?
These are products turned on an automatic lathe, either computer controlled or cam driven (single spindle or multiple spindle). Typically, parts are produced repetitively from twelve-foot bars, making parts with high degree of productivity and consistency.
What type of equipment should a supplier have for turned parts?
In general, high volume parts are best made on Swiss machines. Shorter run products are best made on CNC machines. If your part has cross-holes or milled flats, they are best suited for multi axis machines.
What are tooling expenses?
The customer should be informed of non-reoccurring costs related to a production order. Cost of tool design and fixtures will not occur on a repeat order. It is best for the customer to have this cost differentiated from the part cost.
Should I request a first article sample?
Most suppliers are willing to provide a first article when they run a new job. This should be requested when the job is quoted. There may be an additional cost incurred.
How do I assure my supplier provides the quality I need?
The supplier should have a quality manager and follow a certified, formal quality system. With your input, your supplier can define effective process control procedure.
How does quantity impact price?
For production machining, quantity has a tremendous impact on price. For very high volume jobs we use different types of machines to reduce cycle time and increase output. Once a setup is completed, production can be run on multiple shifts with efficiencies improving as the job runs longer. Price breaks can be provided for multiple order quantities.
Should the customer consider an annual contract or blanket order?
For a stable part design with steady usage, there is no better way to optimize your cost and your supplier’s scheduling.
What about requirements for heat treating and plating?
Most screw machine businesses have preferred vendors and understand the dimensional impact these finishes have on achieving final dimension requirements. It usually makes sense to have the production vendor provide these processes and maintain certification / testing documentation.