66.3 BONDED POWDERS

---

Basically a loose powder is spread in a layer, and an bonding adhesive is selectively applied to harden a slice. Layers are continually added until one or more parts are completed.

A trademarked name for this process is 3DP (3 Dimensional Printing)

The general sequence is pictured below,

The powders used by this process are starch based/cellulose powders.

Parts can be colored using dyes

The water based bonding adhesive is ???unknown???.

The unbonded powder acts to support the part, and eliminates the need for other supports. This also allows multiple parts in a single build.

After the part is complete the loose powder is removed. Powder can be easily removed from hollow and recessed cavities.

Because the part is made of a bonded powder, the final part is porous. Higher part density can be obtained by impregnating parts with materials such as wax or epoxy. Parts may also be sanded for better surface finish.

As expected there will be some dimensional shrinkage, this will be less than 1% for height and less than 1/2% on the build planes.

A machine (Z402) is produced by Z-corporation, and the details are given below,

Build speed approx. 1.85 in/hr height for a 4" by 8" area

Maximum build volume 8" by 10" by 8"

Layer thickness 0.005" to 0.009"

Printing head is 0.36" wide and has 128 jets

Equipment size 29" by 36" by 42"

Mass 300 lb.

Consumable materials approx $0.65 per cubic inch of finished part

No special environmental requirements

Basic unit costs $59,000

An IBM compatible PC is required to run the machine

Advantages,

- inexpensive

- fast

- complex geometries

- suitable for desktop usage

- investment casting can be done from models

- colored parts

Disadvantages,

- part material limited and not engineering materials

- lower part strength