Mechanical CAD design for premium cosmetic dispensing pen (multi-cartridge shade mixing Ended

I'm developing a pen-shaped handheld cosmetic device that mixes and dispenses a custom foundation shade from multiple base-color cartridges into a jar, based on a formula sent from a companion phone app via Bluetooth. The device has no camera or scanner — all shade-matching happens on the phone; the device only receives a formula and dispenses it.

Design intent (premium, not "gadget"):

Shorter, thicker proportions — should feel like a substantial cosmetic product, not a medical injector pen
Soft-touch matte (or glossy/metallic) finish, not flat plastic
Bluetooth status LED recessed/hidden behind a diffused window, not an exposed visible light
Single gold accent band at the cap/body seam
Embossed or engraved logo, not printed
No visible internals — cartridges, pumps, and mechanism should stay hidden inside a clean exterior
Reference images attached (mood/direction reference — not exact CAD specs)

Functional requirements:

Internal cartridge bay for 3-5 base-color liquid cartridges (open to your recommendation — I've seen designs using 3-4 pre-mixed skin-tone shades, and others using a CMYK+white style base-pigment system; happy to hear which fits the budget and mixing goal better)
A mixing mechanism that combines the cartridge outputs into one blended shade before dispensing — this could be a simple pump-per-cartridge timed-dosing system, or a more advanced flow-regulated/static-mixing approach. I have a hard budget cap (see below), so I'd like your recommendation on the simplest mechanism that reliably achieves consistent shade mixing within that cap, rather than the most advanced option by default
A dispense nozzle/outlet at the base of the device, ideally with basic drip control
Internal space for a small MCU with Bluetooth, battery, and wiring

Deliverables: CAD files (SolidWorks or similar), basic DFM feedback (tolerances, wall thickness, printability), and files ready for 3D-printing a prototype housing. Please flag early if any part of the design (mechanism choice, materials, finish) won't fit the budget below, so we can adjust before finalizing.

Budget: ₹15,000 - ₹20,000 for this CAD phase, within a hard total prototype budget of ₹1,00,000 covering CAD, manufacturing, and components. Looking for someone comfortable with consumer product enclosures and small-batch prototyping, not just architectural/industrial CAD — ideally with some fluidics/mechanism experience given the mixing requirement.

Timeline: 3-4 weeks for this phase, including one revision round. read less