Hard Paste Dispenser Design

I need a compact dispenser engineered specifically for industrial-grade paste, with a working volume below 500 ml. The paste is fairly viscous—closer to a hard putty than a flowable gel—so the mechanism must generate reliable pressure without clogging, while still allowing quick cleaning and re-loading on the production line.

Here is what I am looking for:
• A complete mechanical concept, including ergonomics for one-handed use if possible and a sturdy chassis that will tolerate shop-floor knocks and solvents.
• 3D CAD files (STEP or SolidWorks native), exploded assembly drawings, and a concise bill of materials highlighting readily available components and any custom-machined parts.
• Guidance on material choices for all wetted surfaces, keeping durability and chemical resistance in mind.
• An outline of the dispensing action (e.g., screw, piston, peristaltic, or other) with calculations showing it can push a paste of roughly 200 kPa yield stress at room temperature.
• Tolerances and manufacturing notes so the design can go straight to prototyping.

I will sign off once the model opens cleanly in SolidWorks, the BOM is complete, and your force/flow calculations demonstrate the dispenser can empty a 500 ml cartridge of the specified paste without stalling or excessive user effort.