In this issue:
• Production quality 3D printers
• Tech Tip: Determine Sensor Accuracy Needed
• Application: Hay baler motion control
• and more.

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Leading Brand Launches Production Metal 3D Printer

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*X1 160PRO™ and EXOne® are the property of ExOne Corporation.


ExOne, a global leading manufacturer of 3D printers is introducing a new high-volume metal 3D printer—the X1 160PRO™.* ExOne states that it provides more than 2.5 times the build volume of other systems on the market today. The build envelope is 31.5 x 19.7 x 15.8 in (800 x 500 x 400 mm), so it can produce parts of substantial sizes.

As far as speed is concerned, the throughput rate of the 160PRO is more than 10,000 cm3/hr. 3D printer accuracy can be gauged by x,y and z tolerances as well as minimum layer height. For the 160PRO, X1 specifies a minimum layer height of 30 to 200 µm and for their metal printers, accuracies of +/- 0.13 mm (0.005 in) in components under 75 x 75 x 75 mm (3 x 3 x 3 in); +/- 0.25 mm (0.010 in) in components up to 250 x 250 x 250 mm (10 x 10 x 10 in); and +/- 1.3 mm (0.050 in) for the largest components up to 780 x 400 x 400 mm (30.7 x 15.75 x 15.75 in).

According to X1 multiple parts can be printed simultaneously and six different metal materials, including stainless steel choices, can be printed as well as ceramics and composites. They also claim to have industry-leading density and repeatability. Material data sheets are available on their website.

Determining Position Sensor Accuracy

We need to start with an application, then determine the accuracy and precision that application requires as it relates to an angle/rotary-position sensor. Let's consider an hydraulic valve operation for an actuator and say the valve moving up to 90° needs to be controlled within ±1.0°.

Next, we need to create an error budget and assign maximum error amounts to each part that affects the accuracy of moving the valve. The components involved are represented by the block diagram at left.

Each component in the application contributes to the error total including the fluid the valve is in contact with through its bulk modulus elasticity. However, closed-loop control can compensate for latent valve movement caused by fluid compression so, except for a small delay, we are left with adding up the tolerances of the angle sensor, signal conditioning circuitry, A/D converter, valve driver circuitry and hydraulic valve.

While we can add up the maximum tolerances of the components just mentioned, it will give a result that is a worst possible case. The worst case is unlikely, as all the errors from all the components would have to be operating at maximum error levels at the same time and in the same direction (positive versus negative error values). A more accurate way to calculate an error-budget is using the square root of the sum of the squares for each component, then add up the resulting errors. | READ ENTIRE ARTICLE INCLUDING EXAMPLE |

Farm and Equipment Controls
A large hay baler manufacturer needed a better sensor to improve the performance of two different application functions on their automatic baling machine. The features they required included sealing, accuracy and linearity to enable smoother hydraulic control and have an output suited for mobile applications. The RFC4800 Series of angle sensors met their needs for controlling the bale fork lift as well as turntable rotation and tilt. Metal tines at the intake pull the hay in and feed it to a spooler to create a round roll of hay. Details on the RFC4800 can be found here:

If you have a question about position sensors for your specific application, Novotechnik engineers would be glad to speak with you. Contact us at Email Novotechnik or call 800-667-7492.

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