Problem Description

Camshafts for automobile engines are manufactured using a variety of methods.
They can cause a variety of quality defects, such as:
- porosity;
- hardness cracks;
- casting shrinkage, cavities and holes;
- missing material.

Subsequent grinding can also cause cracks or grinding burns (soft spots). They are caused by variations during grinding operations such as changes in grinding speed, changes in grinding wheel/workpiece position and by the effects of the coolant used.
In the past, attempts to automate test procedures have often failed.

Solution

Complex geometry’s such as camlobes can now be easily tested with standard Marposs N.D. probes.
The Marposs N.D. inspection method is based on the Eddy Current technology.
It is the only method capable of performing N.D. inspections automatically. For this reason, it can be easily installed into a production line for 100% inspection.
The traditional testing procedure, which is usually performed with magnetic powder and/or human evaluation, can be now reduced in terms of inspection time and overall cost.
Cracks as small as 100 microns in depth can be detected, dependent upon the surface finishing and material homogeneity.

Automatic N.D. Testing System

The parts are automatically loaded into the Marposs machine for simultaneous inspection of camlobes and journals.
The probes are equipped with diamond shoes and mounted on followers, which always keep them in touch with the lobe surface.

Minimum Cycle Time: 10 seconds.
Reject parts are automatically segregated.
Detectable Defect
The inspection equipments can detect the following defects:
- porosity;
- cracks;
- missing material;
- blow holes;
- nick and marks;
- grinding burns.

Application for the simultaneous inspection of 10 camlobes and 6 journals (16 probes total)
Automatic measuring trigger on the camlobe’s chamfer machine cycle time: 16 seconds

To know more follow the link: Automatic testing equipment for surface defects

Related posts:

1. Eddy Current for ND Testing
2. N. D. Test on Centerless Grinder

In modern production systems it is indispensable to automate non-destructive checks, not only due to stricter quality standards, but above all because the failure of a mechanical component may affect the user’s safety.

Checking the surface defects of parts (such as cracks, porosity, etc.), the structure of the material and the hardness and depth of hardening, the eddy-current technology offers a testing speed that is higher than that of any other technology in the area of non-destructive checks.

Operating Principle

When a solenoid charged by alternating current (control sensor) is moved close to a conducting material (part to be checked), the alternating magnetic field creates a mutual-induction current on the part.
This induced current generates a secondary magnetic field that induces a current in the coil. The impedance of this coil may be affected by differences in the structure of the material, by the hardness of the material, the depth of the hardening or the presence of cracks or pores.

Follow the link to get more information about the: Eddy Current for ND Testing

Related posts:

1. N. D. Camshaft Inspection
2. Non Destructive Testing by Eddy Current