Quote:
Originally Posted by ferc
detecting plastic transparent component that is formed in the mould. The mold may be damaged if the component stays inside before the next cycle.
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The fact that the part is transparent means that it will be inherently quite difficult to do detection with a vision system. If you could, it would be helpful to get some more details about the setup of the process (what is the physical layout, what are the constraints; also what is the budget?), but here's some initial thoughts:
If the part is thick enough, you may be able to use a distance sensor like I mentioned in my previous post. Some plastics are opaque in the infrared spectrum even if they're transparent in the visible spectrum, so you could use an infrared ranger (usually better accuracy, but only works at closer range), alternatively you could use a ultrasonic sensor (less accuracy, can get them with longer range, works with transparent things), you might have some luck with using a laser range finder (simple ones can be found in hardware stores) even though the part is transparent, as the light would tend to scatter. This could actually be an idea for the primary sensing mechanism, as the difference in surface albedo between the transparent part and the (assumedly) opaque mold could be enough to detect, either with just a photocell or a camera. The effectiveness of this might be hampered depending on the ambient lighting conditions of the area.
There's always the option of some sort of contact sensor as well (i.e. a button that would be pushed when the part was present but released when absent).
Some more random thoughts: is there something else that distinguishes the part from the mold, e.g. is the part heated more than the mold or vice versa so that you could use an infrared thermometer to measure the heat of the surface; a sharp increase/decrease would denote that the part had been removed. These are all based off of the assumption that the sensor would be looking at some sort of "open face" mold.
It seems to me the most obvious solution, though, would be if you could make use of whatever system is responsible for removing the part (whether human or machine) to notify you when the removal is complete. If it's a machine, it seems like it should be pretty easy to monitor its state directly (some sort of electronic output from the controller) or indirectly (put a sensor on that machine); if it's human, having a button that says "the part is removed" seems like it might be a better solution from a safety standpoint, anyway, so you know that the operator is out of the machine before you start the next cycle.
This is what I can think of coming from more of a mobile robotics standpoint with a lower budget, not sure if there might be solutions better tailored to your environment.
--Ryan