We refer to the liquids as “ functional agents ” because they aren ’ t exactly ink . One is black ( we call this a fusing agent ) and another is clear ( we call it a detailing agent ), but their job isn ’ t really to color the part , but rather to change the thermal characteristics of the underlying powder . When energy is applied , the now black powder gets hot and melts , whereas the white powder stays cool . A part is built up by printing each layer , fusing , and then repeating . HP has exceptional speed because the drops can be placed down in parallel at 30 million drops per second .
It ’ s InkJet all over again
In 1985 , we could only print black text . Today , you can have an HP-printed 3D part in any
color — as long as it ’ s black . We know how to do more , but black covers a lot of parts . In addition , in 1985 , there wasn ’ t JPG , and Cut and Paste was how you mixed text and graphics — using real scissors and glue . Today , we are also missing the languages to describe the parts we want to produce . In 1985 , we were creating languages to describe a square , a circle , or a font . Today , we are describing how to create a hollow or textured sphere , or how to create a part with gradient strength ( like a hair follicle ).
Our inventors have created extraordinary things — HP has thousands of patents
From pixels to voxels
Just like in 1985 , we had to convert digital picture elements ( pixels ) into dots per inch and figure out color tables to give reflective color that matched expected color . In 3D , we have to convert designs intended for injected molded plastic into slices and those slices into volume elements ( voxels ). We ’ re working on matching color , but we still have to figure out what Gamut means for objects that aren ’ t quite smooth . How do we describe surfaces and textures ?
From paper handling to powder handling
The parallels are pretty amazing . In 1985 , HP had to worry about how deep ink would penetrate into paper , whether we needed to have custom paper or could use “ off the shelf ” paper .
We had to worry about whether the ink was dry before advancing a page . There are amazing parallels in 3D . In 3D , surface texture and part features are tied to the accuracy of placing a drop , the penetration rate of the drop , the size of the underlying plastic powder , the ability to control the fusing of the plastic powder , and numerous other parameters .
In 1985 , Microsoft Word and Excel didn ’ t exist yet . We were at the beginning of languages to describe circles , shading , and splines . There was lots of early work on fonts and treating edges of objects so they looked crisp . There was work on compression , color accuracy , and color perception .
Creating the new language for 3D parts
HP created the Printer Control Language to define how to control printers . In parallel , Adobe created Postscript . These were two different approaches to describing mixed text / graphics . We are there again with 3D . We can match the capability of analog tools where all the material is the
same — but we don ’ t yet have the language for describing digital parts . Parts that have texture , parts where a sphere is partially filled , and parts that have conductive traces . Almost all computer-aided design ( CAD ) tools talk about geometries but not about these digital / voxel material properties .
Just as pixels in print allowed us to manipulate color , in 3D we can manipulate other things . We are working on technology that allows us to manipulate translucency , conductivity , surface finish , texture , and pliability — all at the voxel layer . Each voxel can be different . We now have parts that we can build , but can ’ t describe . There ’ s no CAD tool yet for describing a part that feels like leather or how to make a part the color of a snake .
New design tools will come
The HP Jet Fusion 3D Printing Solution
Just like in 2D , it will be a few years until the design tools catch up to digital manufacturing , but the future is clear . Everything that can go digital will go digital . Just as LaserJet transformed the office printing market , InkJet transformed the home print , Indigo transformed the commercial print / photo market , voxels and Multi Jet Fusion will transform manufacturing . Thirty years from now we will look back to this time as the start of something big that is built one voxel at a time . 3D printing is three decades of InkJet . •
Keith Moore is an HP Fellow , and Head of the Print Adjacencies and 3D Lab , HP Labs , HP . His innovations have been shipped in almost every printer from consumer Inkjet , office LaserJet to large indigo digital presses .
Issue 7 · Summer 2017 · Innovation Journal 21