SOAR VENDING

Senior Capstone Project

This project was a collaboration with three other mechanical engineers to create a hopper for the storage and dispensing of food powders.
It was awarded first place winner in the consumer products section of the Mechanical Engineering Capstone.

Capstone: Intro

Capstone: Image

OVERVIEW

SOAR Vending is a venture working on a protein powder vending machine which will dispense and mix custom combinations of powdered dietary supplements.

The scope of this project was one of 12 individual storage and dispensing modules which will each hold a unique powder.

Capstone: About Me

PROBLEM STATEMENT

The existing hopper (left) has issues with clumping and packing of the powders. A complete system redesign is desired to store, agitate and dispense powdered dietary supplements.

SYSTEM REQUIREMENTS

• 4 inch diameter, capable of storing 5lbs of powder

• Dispenses within 1g of target (usually 30g)

• Dispenses in less than 1 minute

• Compatible with multiple powder types

• Free of cross-contamination

MIXING CONCEPT

Based on a flour system, this concept has a mesh at the bottom. The blades keep the powder agitated and force it through the mesh at the bottom.

RESULTS

• Powder didn't fall through mesh when motor was off

• With small amounts of powder in the hopper, dispensing is consistent and fast

• With large amounts of powder, torque is too high for the motor

FORCED AIR CONCEPT

The second prototype we pursued took inspiration from the agitating system used in some grain silos. Air is forced upwards into the system around the perimeter of the base. An actuator in the center is opened and allows the loosened powder to fall out.

RESULTS

• Powder dispenses consistently in small amounts

• After approximately 10g dispensed, powder clumps and acts as single body

• Turning the system off and back on usually remedies this problem

REDESIGN - MIXER

We chose the mixing design since it was easier to optimize and would ultimately be cheaper for the clients. More mesh sizes were tested and a higher torque stepper motor was chosen. Following advice from an expert, blades were steepened to the powder's angle of repose.

COMPONENTS

Airtight lid with desiccant pocket
Mixer blades
Sifting blade
Mesh
Funnel
Vibration motors
Trap door

SYSTEM OPTIMIZATION

For the most and least flowable powders (best and worst case scenarios), the number of blades and mesh size were varied. The average time to dispense and dispensing precision were recorded and are charted in the heat maps to the left. For each powder, the optimal combination of parameters was chosen.

DESIGN VERIFICATION

Using the optimized parameters determined in the heat maps above, each powder was tested for reliability. The maximum and minimum amounts of powders dispensed are within the system requirements provided by the clients and the curve is centered around the desired value.

Capstone: Projects

RESULTS

Dispenses in around 10seconds
Within 0.5g of desired serving
Can be parameterized to any tested powder

POSSIBLE IMPROVEMENTS:

More secure connection between funnel, tube
Remove vibration motors, add ESD coating to funnel

Capstone: Video