The Importance of a Regular Spindle Evaluation

The second-to-last sound you want to hear in a machine shop is the whine of a bearing on your spindle - the last sound you want to hear is silence.  Looking down the line when you see the flashing red light on the top of the machine, you know you just lost a spindle. 

If you have heard the sound of a bearing whining, you know nothing good is about to happen, particularly if it involves the heart of your machine, your spindle. When this happens, it’s important to contact your machine’s distributor or manufacturer to find the issue and fix it right away to avoid unnecessary downtime.

Don’t know where the problem is? Here are the primary indicators that may be causing problems for your machine:  

1. Motor Stator – For spindles that have built-in motors, check the motor stator condition - check for shorted windings, contamination, and wiring insulation.
2. Spindle Shaft – The shaft has to be straight and taper must be correct for tools to seat and turn without vibrations. Check the taper for contact amount and the face and taper runouts.
3. Bearings - The condition of the bearings is critical. If the bearing preload is lost, the tooling will not be held rigidly and will translate to chatter on the part. Check the axial play to see if the preload is lost.
4. Lubrication – Bearings must be correctly lubricated and free of debris to turn smoothly. Check the lubrication tank level and ensure the fluid is correct to manufacturer’s specification. 
5. Spindle Through Pin – Through-spindle coolant pin maintenance is crucial to maintaining optimal spindle reliability and performance. You can find recommended preventive maintenance outlined in your machine’s operations and maintenance manual. If neglected and coolant passes the seal, the clamping system can be affected and experience issues.  If coolant overcomes the spindle air curtain, it can lead to abnormal temperatures, contamination of the bearing stack, and cause a premature failure. 

Each spindle is different, and each failure is unique.  If the motor stator is shorted, and you don’t need it back for a couple days, a simple stator swap may work.  On the other hand, if you have experienced a catastrophic failure from a crash, etc., full replacement may be in order. Don’t take any noise coming from your machine for granted – it’s essential to stay on top of any possible problems in order to keep all the machines on your shop floor running smoothly.

At Okuma, we want to ensure your machines are always operating at peak performance. To achieve that goal, we offer a courtesy spindle cartridge repair evaluation as one option for our repair and evaluation program, which includes complimentary advice and shipping for your horizontal and machining center cartridge-style spindles.  To learn more about the specifics behind Okuma’s free courtesy spindle evaluation, visit https://site.okuma.com/courtesy-spindle-cartridge-repair-evaluation.