Microplates with ultra-thin walls by two-stage forming

A process for forming a multi-well plate with thin-walled wells, said process comprising:

• (a) forming a plate blank from a plastic resin by injection molding, said plate blank having an initial thickness and comprised of a deck portion and an array of rudimentary wells, each rudimentary well comprising an upper lateral wall section and a lower lateral wall section;
• (b) placing the plate blank so formed in a vacuum forming mold, the vacuum forming mold comprising an array of depressions aligned with the rudimentary wells, each depression configured to accommodate one rudimentary well, wherein each depression is complementary in shape to the upper lateral wall section of a rudimentary well and comprises
• a lower portion that extends below the lower lateral wall section of a rudimentary well accommodated in the depression, and
• a vent hole in the lower portion;
• and
• (c) with the plate blank so placed, applying a pressure differential across the lower lateral wall sections of the rudimentary wells, thereby drawing resin of the lower lateral wall sections into the lower portions of the depressions, to selectively stretch and reduce the thickness of said lower lateral wall sections while leaving said deck portion and upper lateral wall sections unstretched and substantially thicker than said lower lateral wall sections.