Having a different person in each “department” write some copy and then “throwing it up on the website” is anathematic to having a singular voice. A voice that evokes intelligence, capability, experience, and confidence without being self-aggrandizing is probably most appropriate for science and technology companies. But you might want to add other elements for the sake of differentiation: Humorous? Snarky? Irreverent? In any event, choose a voice and stick with it.
Content must speak in terms of what you do—not how you’re organized.
You might have a department that produces one-off products or prototypes that is internally called “Fabrication.” That can connote a lot of different things to different prospects. It can even be pejorative, evoking images of a “mom & pop” welding shop when instead you have a state-of-the art facility for custom precision work. Better to describe it in terms of the particular service provided. For example, Precision Prototype Engineering Development. This is not only a better descriptor; it evokes images of integration and synergies, and can even help your internal customers migrate from a “siloed” mentality to a more collaborative one.
People respond to your brand in two ways: rationally and emotionally. Rational drivers are concrete, have to do with the features and benefits, and tend to be what we first think about when sitting down to write copy. Emotional drivers are equally important but more amorphous, having to do with the “feeling tone” of your website, your brand, your corporate culture, etc.
Spelling, grammar, usage: Errors diminish your message. Professional people tend to be well-read, literate, and so are commensurately sensitive to poor composition, even if they are not “writers” themselves. Poor grammar might not scotch a sale but it is not going to help, either. Also, if you are in an industry where precision and adherence-to-rules are important (think engineering specs, building codes, EPA requirements), then the benefits of intelligent, precise, and powerful copy—written grammatically—are manifest.
Person. People respond best to personal pronouns. Your website content should speak to your prospect the same way as you would to another person, which is in the second person (to her), not the third person (about her). Don’t be afraid to say “your specifications” rather than “the client’s specifications” or “we will” instead of “the company will.”
Consistency. Each page of your website should reinforce the other—not contradict or simply duplicate it. It should also reinforce (or be reinforced by) your print collateral. Too often, printed collateral is developed by one team and website collateral by another, inadvertently working across purposes.