I'm looking for a hydrophobic coating that I can apply to polyester acoustic mesh. The ideal solution would be either a spray or dipping process. Any suggestions?
I'm tyring to find a biocompatible cleaner for a polycarbonate medical device component. We have recently failed ISO-10993 irritation testing on parts cleaned with Oakite 61B. We are suspecting the cleaner. Any help you can provide would be helpful. Thanks.
Hello, I am searching for USP Class VI plastic resin suppliers and I'm struggling to find good options. GE and DOW have a few resins available and there are many food grade options out there. I am looking specifically for LDPE and HDPE resins.
Can someone point me to a listing of medical grade...
I am new to injection molded medical devices. I am designing a plastic part that will go inside a person's mouth.
The part must satisfy the ISO 10993 biocompatibility standards (cytotoxity, sensitization, and irritation). I would like to start by doing some prototype molding for clinical...
Hello, I'm looking for an automotive brushless dc motor controller vendor. The controller will be less than 1kw, operate a small motor at 20,000 rpm. The controller will operate at up to 450 VDC. Operate on hall sensor feedback. Must have CAN control capability. The vendor must be capable of...
Hello,
I am encapsulating an electrical coil in PPS ("Ryton") to seal it from a harsh operating condition that includes hot water. I need to pass the electrical hookup wires through the plastic. There must be a very good bond between the wire insulation and the plastic to prevent electrical...
I am designing a high speed (20,000 rpm) machine with 1/2" bore grease packed ball bearings. The bearings are installed with an interference fit onto the shaft. I am looking for a clever way to anti-rotate the outer bearing race and still provide axial motion relative to the stationary housing...
I am high-voltage testing a brushless DC motor winding and I am reaching the corona inception voltage near 1500 VAC, as indicated by noise and glowing. I've read through other threads on this topic and its still not clear to me if this "glowing" is a potential ignition source.
Is this...
I am designing a small 2.5" stator OD, 250W, internal- rotor, permanent magnet, brushless DC motor. The motor is driven by a PWM based variable speed inverter that will see a 435VDC on the bus.
(1) Is it critical that the motor stator be grounded to the blower frame? there is no way for a...
I recently did a back-to-back test on R6 bearings running at 12,000 RPM. In the first test, I used Nye Rheolube 374-C (NLGI=4, lithium soap thickener) and the machine ran very smoothly. I replaced the bearings with new bearing lubed with Krytox 205 (NLGI=2, Teflon thickener) and I now hear a...
I am in the process of testing a new air blower. The impeller is injection molded with glass filled Ultem. After about 10 hours of testing with air temperature around 65C there is a noticeable increase in the material brittleness.
Do you think these low temperature could increase brittleness...
Hello,
I would like to see some discussion about high-speed brushless motor & controller design(60-120kRPM, 1-5kW). Our biggest challenge is preventing rotor heating and maintaining stable speed control. We currently are using two-pole segmented magnets, segmented magnet sleeves, high...
I am searching for resources (books, websites, consultants, etc.) that I can use for assessing manufacturing costs in high volume production (i.e. plastic injection molding, die casting, sand casting, investment casting, machining, etc.). I need help making high level cost assessments of...
It appears that my motor is generating heat in the magnet or the rotor yoke. Under what conditions does rotor heating occur? What advice do you have for reducing it?
Thanks.
I am looking for a casting epoxy that has good mechanical strength and high tempererature capability with a low CTE. We've tested BisA with 20% glass microbubble fill and have measured 25 uin/in-degF. We measured unfilled to be 35 uin/in-degF. I need an epoxy with a CTE around 13 uin/in-degF...
I would like to use an engineering plastic for a blower housing, but I have concerns about the bearing support. Does anyone have experience using plastics to support bearings? What plastics do you recommend? How do you deal with thermal growth incompatibility? What about thermal issues -...
I am searching for an epoxy resin that has a low coef. of thermal expansion (in the neighborhood of 10 uin/in-degF). Does anyone have recommendations for suppliers, websites, or materials that I can look in to? Thanks.
I need some creative ideas for getting the heat out of the windings of a brushless dc motor. I'm considering potting the windings with a thermally conductive epoxy or thermoplastic. Does anyone have experience doing this? Are there any other methods of improving the conduction path from the...
