Chair Design Series, Part 2

Wood Magazine

In this part, I will be making adjustments to the chair following recommendations from a Wood Magazine article, Must Have Measurements For Comfortable Seating; Pallozorodcarlocom; and measurements from sitting in chairs. The adjustments I make will be specific for me. If you are following along, alter dimensions for your personal comfort.

Must Have Measurements for Comfortable Seating chart

Adjustmentcm
ASeat height (from floor)16-18″18 1/8″46.0375
BSeat depth15-18″17″43.18
CSeat width16-20″16 1/2″41.91
DSeat angle0-5°-2°——————
EBack height12-16″16″40.64
FBack angle5-15°10°——————
GDerriere clearance3-8″9″22.86
HArm rest height7-9″Not applicableNot applicable
IArm rest depth8″Not applicableNot applicable
JArm rest width2″Not applicableNot applicable
KArm rest distance19″Not applicableNot applicable

3D Printer Enclosure & Indoor Air Quality

Top

Should you enclose your 3d printer to guard against volatile organic compounds (VOCs) and ultra fine particles (UFPs)? Expert reports say yes, if you are operating your printer in a poorly ventilated space.

3D printers are electronic devices that heat material to a melting point and as such, emit VOCs and UFPs. If one visualizes desktop 3d printers as small manufacturing machines, it becomes easier to accept that principles of worker and environment protection followed by industrial factories can apply to oneself and one’s home.

Objects that burn or heat are generally sources of VOCs. According to the American Lung Association, VOCs are “are gases that are emitted into the air from products or processes.”  Other sources include: Flooring, carpet, pressed wood products, varnishes, copiers, glue, cosmetics, deodorants, and dry-cleaned clothing.

Burning and heating objects usually produce UFPs as well. “Particles that are less than 100 nm [nano meter] in diameter are commonly defined as ultrafine.” link Cooking appliances, candle burning, and heating devices are a few of the other sources of UFPs.

3D printing has been researched for more than a decade. Information is available in reports outlining emissions from 3D printers. Excerpts from three reports and a blog post are included in this post.

Use the index below to jump between sections of this post.

Photo credit: yoan carle

3D Printed Parts to the Rescue!

This cabinet marks my first attempt at building a cabinet with pine wood. I made many mistakes; however, I was determined to complete the cabinet. With a little imagination, I put wood pieces together with dowels and 3D printed parts to make an attractive piece of furniture for my bathroom.

3D printed door center & handle

The center panels are re-used backs from an earlier, partially failed cabinet project.

3D printed braces & shelves

The shelves are re-purposed sides from the same prior project as mentioned above.

3D printed angle braces

The deep groove in the wood was the result of kick back from a table saw.

The finished cabinet measures 17 7/8″ W x 26 1/2″ H x 11″ D. Wood cut from 2 – 1″ x 12″ – 6′ common boards purchased at Home Depot – $27.

Chair Design Series, Part 1

This is the first of an undetermined number of posts in a chair design series. My goal is to make a completely 3D printed, functional chair based on Enzo Mari’s chair from his book, Enzo Mari – autoprogettazione? My plan is to spend a fair amount of time designing the chair before I begin printing. I will be exploring ways to minimize elements while optimizing a design suitable for printing in a 600 cubic millimeter space. Instructional videos will be included. At the end, I should have a well-designed 3D printed chair and anyone participating should have one as well.

Enzo Mari is an Italian artist and furniture designer. The photograph above is a copy of page 52 from the second edition of his do-it-yourself book; free to everyone except factories and traders. I have three reasons for starting with Enzo Mari’s design instead of starting from scratch: His design is fine and simple; I have attempted making seating before; good chair design is tricky.

I made a hamper stool in 2017 that was in service until Summer 2019, at which time I dismantled it before moving. What I learned from this is that seating looks easy, but requires some engineering to be useful for long periods.

Later the same year, I made what I originally intended to be a bar stool. When I sat on it I realized I missed the mark and it became a table.

YouTuber, Design Squad Global, made a video about employing triangles to provide good support for seating. I have tried adding triangles to designs, hoping to replace material needs, but when I placed parts in Cura for slicing, I found I had not saved much on filament or time.

Plus, I did not like looking at the triangles and I just wanted to cover them. The render to the right shows triangle cubes I imagined could be used as a divider in my living space. It just looks horrible.

In the video below, I show how to put the chair together according to Enzo Mari’s design. When I revisit this, I will experiment with ways of changing the design.

Video 1
Video 2

3DBenchy & Me

I have seen photographs of Benchys for years and I did not understand why so many people printed one. It was not until I found a benchmark tool created by Kickstarter and Autodesk last month that I bothered to find an answer. I did not realize that it is an actual bench-marking tool. After owning a 3D printer for four years, I downloaded a zip file from Thingiverse and printed my first Benchy.

The instructions for 3DBenchy are to: “Print and check your 3D-printer’s result for dimensional accuracy, tolerances, warping and deviations related to changes in printing parameters and material types.” Dimensions are provided for its various sections.

What’s Next?

After you print 3DBenchy, you are kind of left hanging. It was suggested that you post a photograph and get feedback from a community. I did that, but I did not receive any suggestions about how to improve my print. I did not ask for feedback. Maybe I should have. Anyway, it left me wondering how to determine what needed adjustment if 3DBenchy did not look okay.

I found a YouTube source offering explanations; Thomas Sanladerer, “Improve Your 3D Prints.” Sanladerer printed a Benchy in TPU and responds to tweets during the video. An index with starting times is below.

TimeNotes
2:08“Retracts need a bit more length with a flexible material. So, you can very easily get rid of strings by either lowering temperature or increasing retracts. ” Shows over temperature artifacts…
4:12Z banding – Filament not feeding consistently. Print slower. Likely cause is extruder tension.
9:31Z wobble…
20:46Over extrusion
37:45Tree ringing- Not enough resolution to produce a smooth wall; has micro-stepping artifacting.
40:09Partially clogged nozzles or extruder issues
Notes from Thomas Sanladerer’s Improve Your Prints video

What Else?

3D Benchy has been used to compare printing services and slicing software. All3DP did a comparison of printing services. Benchys ordered from i.Materialise, Meltwerk, Sculpteo, and Shapeways were compared based on sintering white plastic polyamide. Shapeways was my go to source for printing before I bought a printer.

Gary Purcell printed a standard 3DBenchy, using 6 popular 3D Print Slicing Programs, and compared the results. Slicers: Beta Kiss v1.6.1, Craftware v1.14, Cura v3.0.4, Ideamaker v2.6.0.925, Simplify3d v4.0, and Slic3r v1.29. Watch the video to see which one performed best.

Reflections

It took a long time for me to print 3D Benchy, but I am glad I did, finally. It led me to learning more about how to make better prints.

Fascinating Finials

I designed this finial and hook for my bedroom windows and along the way I fell in love with the color magenta. Somehow, during my life, I missed the fact that this color is between red and blue. I always thought of it as a pink and it isn’t. Pink is a whitened red. This fuchsine, fuchsia, or magenta has a cooling quality. I experienced it first hand as I had printed a finial in red initially and placed in on the rod. The red was too much of a bright but uninteresting color in that position. I felt the mix was perfect when I changed to magenta. It was colorful enough to demand attention, but did so in a relaxing way.

Models were made in Blender and Tinkercad. All parts were printed on a Creality 10s mini printer with colorFabb’s PLA/PHA magenta filament.

Digital Craftsperson

Creality CR-10 Mini printing part of a table top

“…we’re getting to a point where people understand that 3D printing doesn’t exist for the sake of 3D printing. It’s a tool that unleashes creativity. It’s an instrument that enables all of us to become digital craftsmen.”

Avi Reichental (cited by Davies, Leaders of the New School…, March 29, 2019: TCT MAG)

3D printing has really branched out in the past few years. One of the branches, Desktop Additive Manufacturing (AM), has symbolically climbed only one rung of a ladder to the heights it is capable of reaching. Not everything can be made by 3D printing; yet, a lot of what is used in a home, for example, can be made there and customized to fit the aesthetics of the person doing the printing.

Home products are the main focus of my 3D printing efforts, as I do not have space for an adequate wood workshop, but I do have space for a desktop printer. My prints are all made with filaments that are non-toxic after printing. I have an enclosure for my printer and a nano air purifier to handle ultrafine particles emitted by the printer’s hot end. The printer and its accessories integrate suitably into my living space.

My main goals for this blog are to share my work; inspire others to design and print home products; promote Desktop AM as a means to improving life quality; and disseminate information important to Digital Craftspeople. I look forward to having meaningful interactions with others interested in Desktop AM.