Injection molding process and product produced using the same
AssigneeSiO2 Medical Produts, Inc.
InventorsJean-Pierre Giraud, Herve Pichot
Life of this patent
Estimating the term…
Abstract
A method of molding a solid article such as a syringe with zero draft or very low draft is disclosed. The method includes heating a low draft mold to expand it, then injection molding the part, followed by cooling at least part of the low draft mold element to thermally contract at least a portion of the low draft element away from the solid low draft formed surface sufficiently to release the low draft element from the low draft formed surface. Syringes and other articles formed by this method are also disclosed having and interior draft angle of 0 to 0.5 degrees, optionally at least substantially zero degrees. The syringe plunger can be selectively coated with lubricity coatings and other functional coatings to improve performance of the syringe.
Claims14
A method of molding a solid article, comprising:
- providing multiple-use injection molding equipment including a substantially rigid surface defining a cavity and a substantially rigid core, the cavity and core defining a molding space between them, at least one of the cavity and the core being movable with respect to the other along a parting axis to open the molding space for removing molded articles, at least one portion of the core being a low draft element having a draft angle of from greater than 0° to 0.5 degree with respect to the parting axis;
- heating at least part of the low draft element to a first selected temperature to expand it;
- before, during or after heating, injecting a fluid molding material into the molding space;
- forming at least a surface of the fluid molding material against the low draft element to define a low draft formed surface;
- solidifying at least the low draft formed surface to provide a solid low draft formed surface;
- cooling at least part of the low draft element to a second selected average temperature less than the first selected temperature to thermally contract at least a portion of the low draft element away from the solid low draft formed surface to create a clearance between the low draft element and the low draft formed surface sufficiently to release the low draft element from the low draft formed surface;
- parting the cavity and core along the parting axis;
- and
- removing the solid article from the molding space without causing defects on the solid article.
Dependencies are inferred from the claim text.