Review on NEMA 17 Stepper Motor With Built-In 400Mm T8 Lead Screw For Improved RepRap Prusa I3 3D Printer Z Axis Or CNC Machine Performance - Iverntech by Michael Baird

My unit lasted all of about 300 seconds of total operating time before seizing up. The load was all of 2 ounces, requiring 6 inches of travel. Worked fine the first day as I was assembling and testing. Then, coming back 3 days later to use it was totally locked up. I swapped in another NEMA17 stepper and that worked perfect, so my controls and electrical are all fine. I tried working the motor by hand once disconnected and, at first, it wouldn't rotate at all, Eventually, it began to rotate but slowly and with serious resistance. Extremely disappointed.UPDATE: After reading my review, the manufacturer has responded directly and immediately and have been working with me to understand my use case. They have stepped up and are shipping me a replacement unit. This is excellent customer support and I look forward to a working unit.