Poorly managed with little regard to employees
The company does it's hiring through staffing agencies and, the chances you'll be hired permanently are very slim. Many of the people I worked with were never hired and had worked through the staffing agency for, in some cases, a year or more. However, should you be hired into the company the pay increase isn't very much and, you still won't have benefits as the company only allows you to work 37.5 hours a week (under 40 hours, no benefits.)
As stated, you're allowed 37.5 hours a week which makes you a part time employee, but, you're expected to work on weekends and even though you're working well over 40 hours on top of losing your time off, you're still only a part time employee.
Management rarely understand the product they're manufacturing on the floor but will consistently tell you or suggest that you're doing it wrong. The floor manager is the same fellow you see in those movies from the 1950's that stares you down as you work (I kid you not.)
It's a toxic work environment.
No benefits, part time, weekend overtime expected of employees, poor management