3D Print Mortise and Tenon Joints Round-backed Armchair

Refer to chinese style restaurant, it is very easy to remind us of traditional design element such asarmchair, piercing partition, engraving ceiling and so on.

The round-backed armchair is a rarity in the antique traditional furniture of our country.

The structures of this 3D printed round-backed armchair is mainly of mortise and tenon joints,without any adhesives.

I'm most proud of this.

Modeling Software：Inventor Professional 2018

3D Printer：Flashforge Inventor II

Spend Time：3 Days

Owe to the perfect Sunmao, Chinese antique furniture is able to keep firm for hundreds of years.

A mortise (or mortice) and tenon joint is a type of joint that connects two pieces of wood or other material. Woodworkers around the world have used it for thousands of years to join pieces of wood, mainly when the adjoining pieces connect at an angle of 90°. In its basic form, it is both simple and strong. There are many variations of this type of joint, I need to find the right one which can be printed.

I also research so many sample armchair to look for which type of the mortise and tenon joints they used.

Finally, I choose the Reed Angle Tenon.

I used Inventor to modeling the pieces, then printed them out and assemble them together to test the tolerence and minimum size. I spend much time to do the testing works. But it is, I assure you, worth it.

You need to pay attention for this：

1. The mortise and tenon size. The legs of a round-back armchair should not be too thick, so the mortise and tenon size should not be too large. However, 3D printing is too small to be realized, and even if it can be printed out, it can be broken when assembled. Therefore, it is necessary to determine the minimum size of tenons and mortises, to ensure that they can be printed out completely, and assembly will not break. The result of the test result show me, the minimum size is 3 millimeters, which can be printed completely.

2. The print tolerence. To assemble all the parts without any glues, and to be solid enough, the tolerence shoud be very harsh. In the beginning, I used 0.3 millimeters and find it loosely assembled. Then, it was changed to 0.2 millimeters. It was very difficult to assemble by hand, and finally knocked it with tools. During this process, the parts are not broken and the assembly is firm. However, I want to remind you that if you use the different 3D printers, printing compensation settings should also be changed accordingly. The 0.2 millimeter here can only be a reference for you. It should be determined by your own test results.

I collected data and studied the structure of various armchair. The upper and lower body of the armchair should follow a certain proportion, the upper body too high will make the chair looks top-heavy, the upper body too low will looks dull. So, I drew this design draft.

Autodesk Inventor is a computer-aided design application for 3D mechanical design, simulation, visualization, and documentation developed by Autodesk.

Autodesk Inventor includes powerful parametric, direct edit and freeform modeling tools as well as multi-CAD translation capabilities. I always use Inventor to create models duiring work, so I am very familiar with it.

It is not hard to modeling the chair's body part. I just create the left part, then mirror to the right part, it is easy.

But I had a trouble when created the round-back. That afternoon I was passed in ascetic meditation.

Bingo! I found the key point. Actually, the round-back was placed in a planar reference to picture I marked use red color.

So, I created a plan, draw the sweep path on the plan, draw the profile on the vertical plane, sweep will get the half part and mirror another part.

Next, 3D printer started to work.

The round-back have a little difficult to 3D printing. It is too large, so it was unable to stick firmly on the printing board.

Other pieces were easier to printing out.