$50 MOBOT and ERP

[pomprocker]

What is that black material that is used for the base in the documentation of these two robots?

[Webbot]

these two robots

Some kind of link would help. We know lots of robots 

[pomprocker]

its on the SoR pages here under robots.

[cooldog]

there ared 19 of them which one

these 2

http://www.societyofrobots.com/robot_ERP.shtml

http://www.societyofrobots.com/robot_mobot_2007.shtml

i thinks it's black HDPE (does it come im black?)

[pomprocker]

I was thinking either carbon fiber or acrylic

[Admin]

I think its acrylic (or delrin?), I forgot what I used . . .

Its my new favorite material

[pomprocker]

Why is it your new favorite matierial?

HDPE has so many good properties!

[Admin]

The best part of HDPE is its the easiest material to cut yet its still strong and lightweight and cheap.

However, the material is soft, scratches easily, and isn't that rigid. The translucent color also doesn't look as professional as a pure white or pure black color (like on my ERP).

Acrylic, nylon, and delrin have the advantages but not those disadvantages - but typically more expensive . . . Since money isn't a factor for me anymore, I no longer use HDPE . . .

Just search for those materials at mcmaster.com to compare - you may discover new options!

[pomprocker]

What kind of thickness do you recommend on acrylic/delrin?



I found this place in Southern California, in Anaheim right next to the Angel's stadium that offers will call pickup.

http://www.indplastic.com/


I just bought some HDPE there, very good service

[Admin]

What kind of thickness do you recommend on acrylic/delrin?

1/6" is strong/rigid enough, but I often use 1/4" so I can tap it and put spacers and screws into it securely.

Oh, and its a bit heavier than HDPE, but I cut large holes into parts to reduce weight - like in the arms of my ERP.

[pomprocker]

How is the caster mount on these two robots constructed?

[Admin]

There are two flat plates with holes drilled halfway through the center of them. Then I used a .25" rod and placed it into both holes, with the rod also inside the caster wheel.

[Admin]

Ok I looked it up.

I am using delrin on my ERP. Its about twice as strong, twice as rigid, heavier, and about twice the price of HDPE. In fact, I used about $80 worth of delrin on my ERP (per version).

However, because its so much stronger, I can use my CNC and FEA to cut away large holes into all my parts to dramatically reduce weight without sacrificing strength. If I didn't have a CNC or money to spare, delrin would probably not be my new favorite material.