Choose the Right CNC Machine Tool for Your Parts

Customers sometimes ask us to quote a specific machine model before sending the part drawing. This gives us a starting point, but the model name and maximum machining diameter are usually not enough to confirm whether the machine is suitable. Before making a recommendation, we normally ask for the part drawing, material and estimated production volume. These details help us understand the required operations and determine a practical machine configuration.

The Part Diameter Is Only the Beginning

Maximum machining diameter is an important specification, but it should not be the only basis for machine selection. Two parts may both be produced from a 12 mm bar, yet require different machines. A short and relatively simple component may be suitable for a fixed-head lathe. A long, slender part with fine threads and several side features may be better suited to a sliding-head type (Swiss-type) lathe with a guide bush, live tools and a sub-spindle. Part length, geometry and machining features must therefore be reviewed together.

We also check whether the component requires rear-side machining, cross drilling, milling, tapping or angled features. These requirements affect whether the machine needs a sub-spindle, Y-axis, B-axis or a particular live-tool arrangement. Additional axes can provide greater flexibility, but they are not necessary for every application. If a simpler configuration can complete the part efficiently, it may offer a better balance between machine cost and production requirements.

Information Required for Evaluation

A clear 2D drawing or 3D model is the most useful information for our initial review. The drawing allows us to check the dimensions, tolerances and machining features of the component.

We also ask customers to provide:

• Workpiece material
• Raw material or bar diameter
• Critical tolerances
• Surface-finish requirements
• Estimated monthly or annual production volume
• Required cycle time, if specified

If the component is already in production, information about the current process can also be helpful. For example, the customer may want to reduce cycle time, combine two operations into one machine or improve the stability of a particular dimension. These details help us understand the reason for the new machine investment, rather than simply selecting a model that can accommodate the part diameter.

How SELICA Reviews the Application

Our team first checks whether the part is suitable for CNC turning and whether a sliding-head or fixed-head machine would be more appropriate. For long and slender components, the support provided by the guide bush can help control material deflection during cutting. For shorter parts, particularly those with a larger outside diameter, a fixed-head lathe may provide a simpler solution. The next step is to arrange the machining operations. We review which features can be completed on the main spindle, whether the part needs to be transferred to a sub-spindle and which tools are required for the rear-side operations.

Material must also be considered. Titanium alloys, stainless steel, brass, aluminium and carbon steel have different cutting characteristics. The material may affect spindle-speed requirements, cutting-tool selection, coolant delivery and chip control. Production volume influences the recommendation as well. For small batches, setup flexibility may be more important than the shortest possible cycle time. For continuous production, the bar feeder, tool life, chip removal and parts collection require greater attention. The machine and its accessories should be evaluated as one system. Collets, guide bushes, tool holders, bar feeders and coolant equipment all need to match the workpiece and the intended production method.

Send Us Your Application

Customers do not need to decide the complete machine configuration before contacting SELICA.

To begin an evaluation, please provide:

• Part drawing
• Workpiece material
• Expected production volume

You may also include the required cycle time, current machining method and any production problems you would like to improve. Based on this information, SELICA’s sales and engineering teams will review the part and recommend a suitable machine, tooling arrangement and related equipment. With many years of experience in CNC turning and precision machining applications, we aim to provide a solution that is practical for the part, the production target and the customer’s budget.