Jeff, I totally agree with you. A one time permanent fix as opposed to constant tweaking is always preferable. By the way tolerances are given for a reason. Once you have solved the problem to consistantly be, not only within tolerance, but exceeding by a factor of 4, any further messing around is a waste of time and money. Well done kyoshi.
Thank you for the compliment. It did work out as almost the ideal engineering solution, solving a long-standing product issue with no additional cost other than the initial programming of the Blohm grinder. The sensor based approach would be a fascinating project to try for an order of magnitude improvement over current best practice for "standard" machine tools.
As a control engineer, I am fascinated by the measurement approaches suggested. As a mechanical/project engineer, I am on the side that says if you can grind in the compensation on each part and you get what you want in terms of accuracy, you should. Any kind of sensor can eventually fail, connections fail, and sensors always needs to communicate with the controller. If you don't have those components in your design, you won't have the failure mode, you won't have to put them on the BOM, inventory or buy them. I think this is a great solution.
I appreciate your input. With the wide range of sensor technology available today in conjunction with inexpensive computational power a self-correction machine tool could obtain incredible levels of accuracy.
If you were using an angular sensor with a reference to the work surface you could make linear corrections to the position to compensate for the positioning error introduced by the angular motion of the structure. The linear correction of 5 ppm per arc second would be dependant on the the distance from the linear measurement reference for the Y-axis. Angular motions would still be introduced at the tool, possibly creating inaccuracy when large die sinking tools are used.
The machine in question is a relatively rigid structure, the angular deflections were extremely repeatable under a range of operation conditions. Real time measurements would be more expensive (and less effective) than mechanically compensating for the underlying structural deflections.
I agree with you, but inorder to make corrections and ajustments you need to make measurements. This is a real time sensor, so while you see what are the errors in position, you can make correction.
The workpiece is attached to the table, the diesinking form tool is attached to the bottom of the Z-axis. Angular errors, positioning errors, straightness and squareness errors will all produce unwanted deviations from "perfect" in the finished workpiece. Improving the machine accuracy will improve the accuracy of the workpiece, measuring the errors will only tell you how much error you are introducing into the workpiece.
If I understand it correctly, you have one reference surface and then the other that changes its orientation. You can use a unit called EZ-TILT-5000, that reads two sensors and can provide you with individual angular orientation of each sensor and also the differencial. This way you can always see the actual deviation of the required surface in reference to the standard.
It looks like a great sensor, but I am not sure how you would compensate for the angular error in this example. The angular machine deflection is referenced to the machine table, and a mechanical compensation is necessary to maintali Z-axis squareness to the machine table (and workpiece).
We looked at a number of sources to determine this year's greenest cars, from KBB to automotive trade magazines to environmental organizations. These 14 cars emerged as being great at either stretching fuel or reducing carbon footprint.
Researchers at MIT and Sandia National Labs have observed a reaction in lithium-air batteries that could help improve the design of these cells for electric vehicles and other applications.
Healthcare might seem to be an unlikely target application for the Internet of Things technology, but recent developments show small ways that big-data is going to make an impact on patient care moving into the future.
From Dell / Intel® New Paradigms in Design Work Scott Hamilton, vertical market strategist for Dell Precision workstations, 5/2/2013 3
Early in my career, I worked as a draftsman and remember the days of drawing on vellum with numbered pencils and Mylar with plastic lead. This was a fun experience in the sense that I ...
I've been using workstations for more than 10 years and love finding ways to get more performance from my system. With demanding professional applications that require more power each ...
A lasting memory from my first job as an engineer in an auto assembly plant is standing on hard concrete at six in the morning, vending-machine coffee clutched in hand, listening to ...
A quick look into the merger of two powerhouse 3D printing OEMs and the new leader in rapid prototyping solutions, Stratasys. The industrial revolution is now led by 3D printing and engineers are given the opportunity to fully maximize their design capabilities, reduce their time-to-market and functionally test prototypes cheaper, faster and easier. Bruce Bradshaw, Director of Marketing in North America, will explore the large product offering and variety of materials that will help CAD designers articulate their product design with actual, physical prototypes. This broadcast will dive deep into technical information including application specific stories from real world customers and their experiences with 3D printing. 3D Printing is
To save this item to your list of favorite Design News content so you can find it later in your Profile page, click the "Save It" button next to the item.
If you found this interesting or useful, please use the links to the services below to share it with other readers. You will need a free account with each service to share an item via that service.
Tweet This
0 
