Standards in the automotive sector and many other industries are requiring the continuous control and inspection of safety-relevant components during the manufacturing process and prior to shipment to guarantee the expected yield from an outstanding product. It’s no longer sufficient to test the geometric dimensional features of a component; material quality, functionality and aesthetic attributes have to be checked to prevent major economic consequences in case the part doesn’t meet the application requirements.
Structural failure can be catastrophic not only in terms of material/replacement costs, but also for indirect costs related to the loss of company reputation. Even the smallest defects must be found, sorted and reported during the inspection process. Thin cracks, often invisible, can open and compromise the part functionality under permanent load. In the worst scenario, this can lead to component failure and could activate the well known process of product recalling campaigns.
Non Destructive Testing (NDT) with Eddy current stations has become crucial for comprehensive process control, especially for the inspection of thin cracks spotted in the material surface. Partnering with the most important NDT device manufacturers for the Cracks Control detection, Dimac has renewed all the machines of the range with state of the art NDT stations capable to perform this control with the highest accuracy and productivity rate possible.
Combining speed with accuracy
The cycle time required to perform a reliable Eddy current crack detection on safety components does not allow to reach high speed in controlling and sorting the parts. Sorting machines with conventional Eddy current crack detection stations allow to output at least 150 parts/minute. Dimac developed and patented MCV4 which is a double rate running inspection machine. This piece of equipment is capable to control 2 different parts simultaneously with 2 different Eddy current stations leading to a productivity improvement up to 65%-70%, up to 250 pieces/minute.
In the Dimac MCV4, each Eddy current station for crack detection is able to pick-up the part and rotate along its axis of symmetry, in front of the Eddy current probe. This pick’n rotate system ensures a very stable rotation of the piece without tilting. The position and the angle of the probe with respect to the part geometry are kept constant by a dedicated adjustable carriage. The availability of master OK parts and of boundary NOK samples with cracks is mandatory for the setup of the stations, in order to minimize the pseudo-rejects ratio.
The man-machine interface is absolutely user-friendly. The setup is intuitive and based on a simple teach-in procedure, where the multi frequency testing electronics provides a complete scanning of each piece. The results are immediately displayed on the screen, the thresholds envelopes are calculated and could be optimized thanks to a smart wizard procedure.
The MCV4 double rate incorporates also twin stations for the complete dimensional control of the parts all around 360° with high-res digital cameras. Two parts could be controlled simultaneously for their overall outside geometrical features and for mechanical recess inspection. The patented MCV4 concept cuts the time and the costs for the 100% sorting process when cycle-time consuming controls like crack detection and 360° all around inspection are required.
The MCV4 covers a range from M4 to M16 with shank length from 15 mm to 120 mm. It also features a dedicated evacuation exit for the NOK parts with cracks only. Productivity is guaranteed thanks to a recycling circuit for the pseudo-rejects or not controlled parts which are not evacuated until controlled and judged a second time. Output rates are estimated up to 250 pieces/minute with Eddy current crack detection and 360° all around visual inspection with multiple frame. Higher rates up to 850 parts/minute could be reached with standard visual controls by high-res cameras only.
