A plastic mold to make Arepas

I am Venezuelan and love AREPAS!

Arepa is part of our culture. The arepa is also becoming very popular in many places in the world due to the massive immigration of Venezuelans leaving the country scaping of the terrible economic, social, and political disaster of the last 20+ years.

The arepa is made from pre-cooked cornmeal. The most popular brand of cornmeal used to make arepas is P.A.N.  You can find "Harina PAN" practically anywhere,

The video is self-explanatory:

Fix it, Don't trash it!

New toy, new activity!

Yes! I have now a brand new 3D printer and my first project after 9 hours assembling, testing and a bag of Haribo bears courtesy of Joseph Prusa,  was to fix my foldable hand truck.

I hate to trash things if they can be fixed and I kept may danged foldable hand truck waiting for the 3D printer. A plastic part that locks the folding mechanism broke months ago so it was unusable. With the help of Fusion 360, a caliper and my new 3D printer I made the new part and now I have a working hand truck 👍😀

The Suprematist Time Keeping Machine

The Suprematist Time Keeping Machine

I made this clock as a present for my younger son to decorate his new home. 

The idea of this clock started during a visit to the National Art Gallery in Washington, DC. In the modern art section, there is a sculpture created in 1915 by the French artist Ivan Puni (1894-1956). Puni was an artist following the Suprematist art movement, very popular in Rusia. Below the pictures that I took at the gallery:

Suprematist Construction Montage

By Ivan Puni (1915-1916)

When I saw the sculpture, the idea of a clock came right away. The black circle will long rectangle as the second's hand, the long rectangle in the red square the minute's hand and long polygon on the black triangle as the hour's hand. The artist used cardboard, paper, and some scrap metals to make the sculpture, some of the paint is fade out by the time. The sculpture is protected with a transparent plastic cover to protect it.

My clock is a replica in the size and shapes of the original sculpture, but I used some other materials for durability and modern construction techniques. I used for the back place 1/4" plywood and dark Danish Oil stain. There is another inverter L shape piece that I think is some kind of stone in the original art, I used MDF with a smoke gray paint. For the square, triangle, minute's, and the hour's hands and circle, I used 1/8" plywood. The second's hand is aluminum.

I built the large cone shape with a brass sheet, the smaller cone shape with a sheet of galvanized steel, and the corrugated panel with an aluminum sheet.

I used for all the wheels, except the motor pinion 1/4" and 3/8"  Premium Baltic Birch Plywood B/BB Grade. 

The clock drive is a stepper motor controlled by an Arduino Nano with an RTC (real-time clock) and a micro-stepping stepper motor drive board. The stepper motors are noisy when running at low speed, even with micro-stepping, so I isolated the motor with rubber spacers and also made a rubber pinion to drive the clock.

All the wheel shafts are 1/4" brass, and all are installed with sealed roller bearings.

Creating the Model:

First things, first! And the first thing is the model, and as usual, I used Fusion 360 to create the 3D model of the clock.

I found the dimensions information on the National Gallery website and started my model with a canvas image scaled at the real size. Below you can see an animation of the transition from the canvas picture to the model:

 

Many hours of work resulted in a model almost identical to the original. There is some small modification in the position of the hour's hand to avoid collision with the minute's hand and to reference a real-time relation between the hours, the minutes, and the seconds. The artist made the sculpture in a way that it almost shows a real hour!

Back to my garage (COVID-19) stay at home. New CNC controller for may 30/40 CNC router

Work, travel, and some health issues kept me out of my garage for a long time.

During these difficult days, doe to my age and previous health conditions, I must stay at home.

My design workload that can be done from home is also low as my customers are also reducing their activities to the minimum necessary, so I am back to my garage.

After a few days of cleaning and reorganizing, I restarted a project that was on hold for a long time: Refurbish my CNC; I have been working on this project on and off for several months during my short home return from my frequent travel schedule.

The scope of the project is:

1. New computer to control the machine
2. Upgrade to MACH4 software
3. New driver board compatible with MACH 4 and Ethernet connection
4. Add a manual pendant.
5. Mechanical maintenance of the router.
6. Add limit/home switches.
7. Add an Axis Z height probe.
8. Add a rotary axis (B)
9. Add a small laser head for engraving.

For the new computer, I used a laptop that my son left when he bought a gaming computer, this is an I5 8GB Ram, running Windows Vista. I replaced the hard drive with a 500GB SSD, installed Windows 10, and bought and installed a Mach4 hobby license.

After in-depth investigation and some failed purchases of driver boards compatible with Mach4, I finally found a good one with a lot of documentation and support, the PoKeys57CNC Motion Controller for Mach4, and now, after using it for some time, I am sure I made the right decision.

The next step was to order all the components and design with Fusion 360 and fabricate the controller box.

I fond all that I needed like connectors, switches, in Amazon. When I ordered the Pokey board, they offer a flat cable and connector kit that makes it very easy to interface.

The two crucial things I added are the pendant and the stepper motor drivers.

I sent the design of the sheet metal case to Protocase, and after the quotation and some engineering questions, I received the metal case in less than a week perfectly made and painted.

Once I got all the parts, I needed about 50 hours to assemble and wire the control and to install the limit, home switches, and the touch probe for tool measurement in the machine.

It took another full week to learn and start the Mach4 software, configure the Pokey in Mach4 and make the first part.

The last upgrade I made is that I bought a Chinese  5.5W led laser head, designed and built a bracket to install the laser on the body of the spindle motor, add the necessary connections to the new control and creat a laser machine profile for Mach4 I am delighted with the results although it is a very inexpensive laser device,

The Time Transparency Clock

Since the last post I have worked hard in the design and build of the Wood/Plastic clock. I have made a lot of changes in the original design, and I think that the final result is really a very nice clock!

It even has a name thanks to my sister! The time Transparency Clock:

Acrylic is difficult to work in the CNC with small diameter end mill bits. I used a 1/16” 2 Flute carbide end mill for the wheel teeth. After damaging several plastic stock and 2 end mill I learned:

• Use new and sharp bit or a sharp bit that has been used only in plastic. If you used a bit to cut wood, forget to use it later in plastic.
• You need to remove very little material each pass :.
• 24,000 RPM spindle speed and 10 inches/minute feed rate.
• Keep the bit cool with compressed air.

For the internal cuts I used a 1/8” 1 Flute end mill. You also need a new and sharp bit or a sharp bit that has been used only in plastic but feed and RPM are different: 15,125 RPM, 16.1 Inches/minute feed rate and .004” maximum step down per pass.

With the above settings, and with lots of patient it is possible to get a very nice and clean cut. Below a video showing the internal cut with 1/8” end mill:



The other complicated thing is to bond brass and acrylic. After several test I ended using 2 part transparent epoxy.

Here is a video showing several details of the clock.


I love the action of this clock!


Happy holidays to all!

New Plastic and Wood clock on the way

After some time way from my garage and design activities I am back with a new idea.

This time will be a modernistic table clock design with several interesting features:

• Combination of wood and plastic: The frame, the base and the dial will be made of wood. The wheels will be made of acrylic.
• All wheels will have an outer diameter of 6”
• This clock will have a seconds hand, but a very special one: retrograde seconds hand
• There will be a lot of “action” in the clock as it will have 5 wheels
• Will be driven by a stepper motor and an Arduino controller

Here is the computer design of the clock.

The clock does not have a name so in invite my readers to suggest one.

Making Mechanical Marvels in Wood with Fusion 360- Part 1

This is an old book! but a very good book for those who want to start building interesting things in wood.

To practice and learn how to use and simulate mechanism in Fusion 360 I modeled all the projects in the book except two.

What I found during this exercises is that Fusion is really friendly and essay to use for and also very powerful. It has some limitations with advance features like motion simulation and contact sets but for general design this things are not very important.

Here are all the models and pictures

Wooden Cam Follower:

 

The wooden Eccentric Mechanism

A Motor model in Fusion 360

The more I play with this software, the more I like it.

The nice thing is that the support and the information available is very good.

I modeled an AC motor to learn to use as much modeling tools as possible.

The program is very similar to Inventor but at the same time more user friendly. It runs slower in my machine compared with Inventor but not a mayor issue.

Below is a very nice tool that allows sharing the projects in a very interactive way.

I hope you like it

 

 

Technorati Tags: Fusion 360,AC Motor,3D

Autodesk Fusion 360 3D CAD reinvented

I am an experienced 3D drafter. In my day to day work I use AutoCAD, Invertor and SOLIDWORKS. I can switch from one to other without major effort. These programs are all very good and well recognized but at the same time very expensive for personal use. All these programs require to have a computer (powerful) loaded and with the licenses. For big projects you need a server to work on collaboration mode and the price of the license per user is several thousands of dollars a year if you need to keep the software up today.

I have tested many open source 3D drafting programs and also  Google SketchUp; some of them pc residents and some cloud based. I did not feel confortable or productive with any of them.

This weekend I downloaded the demo version of Autodesk Fusion 360 and after a couple of hours I registered it and I I fell in love with it. I transferred some of my clocks models to Fusion 360 and started to play around. Then I decided to make a first full drawing of a part, in this case a RC Servo that I will use in a clock. Knowing Inventor the learning process was a piece of cake.

The other good news is that Autodesk Fusion 360 has a very interesting offer:  A free 1-year startup license is also available for hobbyists, enthusiasts, makers, and emerging businesses that make less than US$100,000 in revenue per year. At the end of 1 year, you can reselect the startup entitlement or transition to a commercial entitlement.

After finishing the drawing it is necessary to use a program for generate the CAM to be able to mill or fabricate the parts. Mastercam is an excellent program but  too expensive for personal use. I don’t know any good machine shop that does not use Mastercam. This program is the standard.

I use BobCad-Cam V26 as CAM postprocessor  because I bought it during an offer they had last year at a reasonable price, but I need to convert my work to DWG or STEP in order to run BobCad.  The CAD part of BobCad V26 is not as good and flexible as other programs. I know they made a lot of changes in version 27 and probably is much better now but I am not willing to pay more for something I use for hobby and not for work.

Fusion 360 has CAM as part of the package and also has the postprocessor for MACH3 that is the software I use to drive my small CNC. Now the work will be straightforward: Model – CAM – Mill with the same platform.

The next step will be to create a model of a sprocket or wheel and run the cam to learn and test the results with my small CNC machine.

Conical Clock Overhauled

This clock will go to the hose of a very special person for me and I need it not only to be nice but also accurate. the Conical pendulum is very inaccurate and also has some noise problems. With the changes now the clock is quiet and very accurate.

 

I modified the clock to be driven by a 60 RPM synchronous motor.

I added a double sided contrate wheel and two crown wheels one driven by the motor and the other to drive the pendulum

 

The pendulum has also a inertial wheel. I embossed 12 weights  to the wheel. I also added a new guide for the pendulum rod.

I really like how it works!