Thread mills are the cutting tools that are used to conduct threading, which is the process that creates a screw thread. Sometimes thread mills may also refer to thread mills process itself in the industry.
For the metal working field, there are thread mill cutting, thread forming, and thread rolling. The ways to make threads are many, and each method involves different physical mechanisms and related goals of the application purpose.
Thread mills cutting are the use of thread mill tools to create the threads on an object, and it is adopted when full thread depth is demanded. This method is quite cost consuming so that for normal circumstances, this method is used only when there are several specific situations happens (those conditions are not supposed to happen together as required)
● Small quantity manufacturing
● Inaccurate blanks
● Demanded threading towards shoulder
● Tapered thread
● Brittle work pieces
For these conditions, if one condition is fulfilled, manufacturers need to use the thread mills cutting tools to deal with the work pieces precisely so that they would render the intended working results. However, since this type of machining costs high, so some machine tool manufacturers has developed custom machines that can deal with this requests.
Many machining centers that are designed with tapping functionality can also make thread mills milling process on their working tables and the working productivity is quite amazing to most of the order requests. Besides, an ordinary method people use to thread mills is to cut with taps and dies. The two mechanisms work together to achieve the goal can make the whole process much faster and reduce the necessary expenses. This kind of works belongs to subtractive methods and this is one of the most popular methods that people use to generate threads.
Threading process conducted by single point methods is the operation that utilizes one single point cutting tool to generate a thread shape on a cylindrical work piece or a cone shaped work piece. During the single point threading process, the rotation of the work pieces is decisive to the lead of the thread, and the whole procedure can be achieved to generate outer or inner threads off the work pieces. Outer threads are referred to as the male thread and the inner threads are called the female thread instead.
This working mode involves the role of chuck and cylinders as the necessary components and parts, because the chuck needs to hold the work piece for the outer thread cutting process for the external shapes to be achieved. The same principle goes to the inner threading case. All the movements are done linearly and the actions will take chips off the work pieces with each move of pass. It takes about six cuts to generate one correct and precise depth of the thread form. Cylinders and chucks are important and necessary supports for the threaded work pieces here, and thread mill tools are to be accurately chosen here so that the cuts can be controlled within a reasonable numbers.
For the de-formative threading, the limitations are many, and the formed work pieces are less rigid and precision for some extent if one considers the comparison with traditional thread milling methods. For the materials suitable for this method, there are ductile materials since the threads are cold formed. The de-formative process will increase the yield strength of the threads as well as the hardness and wear resistance. If the materials are suitable for deformation features, they need to be processed by rolling.
Overall speaking, the material features are softer materials that exclude brittle characteristics like casted iron items. In the metal working industry, the term cast iron is a metalworking process that produces a group of iron-carbon alloys with carbon content greater than 2%. Its wide application derives from its relatively low melting temperature. The alloy constituents affect its color when it is fractured. White cast iron has carbide impurities which allow cracks to pass straight through. Grey cast iron has graphite flakes which deflect a passing crack and will initiate countless new cracks as the material breaks happen.
All these methods are just a few options for thread making in the field of thread formation. Both forming method and cutting mechanism are acceptable based on the customers’ demands. It is crucial for manufacturers to know more deeply about the targeted goals of the made screws so that they can choose the thread process and the corresponding facility properly with the best reasonable costs for their own.
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