Page 1 of 2 12 LastLast
Results 1 to 10 of 11

Thread: The name of the material for HROS parts?

  1. The name of the material for HROS parts?

    Hi,

    It has been some time since last post, too much teaching these days.

    Recently I decided to pick up the robot project again, but would like to push this forward a bit. However, I have the questions concerning, which materials are the HROS1 using for the skeleton parts? I guess these shapes are processed by laser cutting?

    http://learn.trossenrobotics.com/cac...y_hros1_p2.jpg
    http://learn.trossenrobotics.com/cac...1_tilt_cam.jpg

    From my poor knowledge, I guess this is some type of plastic, but would like to know exactly which types of plastic. Many thanks.

    Shihui

  2. #2

    Re: The name of the material for HROS parts?

    The specifications say "Lasercut Delrin Torso."

    I'd expect the body brackets to be Delrin (also known as Acetal and POM.)

  3. #3
    Join Date
    Sep 2010
    Location
    ಠ_ಠ
    Posts
    2,172
    Images
    27
    Rep Power
    266

    Re: The name of the material for HROS parts?

    I am pretty sure that the majority of the laser cut parts are still a PMMA/PC blend like the other Interbotix kits (previous versions were ABS). In the HROS-1, there is a single delrin shim taped/glued to the bottom-side of the torso plate to act as a wear-plate/bushing between the torso plate and the hip yaw servos.
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    bleh

  4. #4

    Re: The name of the material for HROS parts?

    This page says "lasercut delrin torso":

    http://www.trossenrobotics.com/HR-OS1

    Additionally, when clicking into "specifications" it also says 5052 aluminum brackets for the frame.

    It doesn't mention the P95G acrylic at all.

  5. #5
    Join Date
    Sep 2010
    Location
    ಠ_ಠ
    Posts
    2,172
    Images
    27
    Rep Power
    266

    Re: The name of the material for HROS parts?

    http://learn.trossenrobotics.com/pro...bly-guide.html

    5052 brackets for servos
    Shapeways SLS nylon head tilt frames
    In-house lasercut P95G 'plates' for 'shoes', torso, etc.
    In-house lasercut delrin hip shim
    Plastic or metal hex standoffs for mounting plates together
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    bleh

  6. #6

    Re: The name of the material for HROS parts?

    Exciting! They probably should update their store listing, then :-)

  7. Re: The name of the material for HROS parts?

    Quote Originally Posted by tician View Post
    http://learn.trossenrobotics.com/pro...bly-guide.html

    5052 brackets for servos
    Shapeways SLS nylon head tilt frames
    In-house lasercut P95G 'plates' for 'shoes', torso, etc.
    In-house lasercut delrin hip shim
    Plastic or metal hex standoffs for mounting plates together
    There are quite some chemistry words to google before I can fully understand, haha...

    Still what does 5052 and P95G mean? I guess it is the specification, but is it plastic or aluminum?

    Thanks tician.

    Shihui

  8. #8
    Join Date
    Sep 2010
    Location
    ಠ_ಠ
    Posts
    2,172
    Images
    27
    Rep Power
    266

    Re: The name of the material for HROS parts?

    5052 aluminum - an aluminum alloy with very high formability, so it works well for bent sheet metal objects like the servo brackets as you can cold form them and not have the bends break or require any post-forming heat treatments to keep most bends from quickly failing.

    P95G thermoplastic - a blend of PMMA/PC (PMMA/acrylic/plexiglas + PC/polycarbonate/lexan); thinking it a 95% PMMA + 5% PC.

    ABS or delrin or polyethylene or polypropylene would all work just as well as the PMMA/PC blend, but plain PMMA would likely break too easily in the torso of a humanoid. The PMMA/PC blend is simply what the folks at Trossen have been using for a while for all their Interbotix kits as it looks nicer than ABS and is safe/easy to lasercut like plain PMMA, but does not break quite as easily as plain PMMA because of the PC content. It does have some of polycarbonate's weakness to threadlocker (a variety of anaerobic adhesives), so have to minimize any contact just like the batch of styrene-rich Bioloid Premium frames that Robotis temporarily released several years ago before returning to a safer ABS-blend.
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    bleh

  9. Re: The name of the material for HROS parts?

    Quote Originally Posted by tician View Post
    5052 aluminum - an aluminum alloy with very high formability, so it works well for bent sheet metal objects like the servo brackets as you can cold form them and not have the bends break or require any post-forming heat treatments to keep most bends from quickly failing.

    P95G thermoplastic - a blend of PMMA/PC (PMMA/acrylic/plexiglas + PC/polycarbonate/lexan); thinking it a 95% PMMA + 5% PC.

    ABS or delrin or polyethylene or polypropylene would all work just as well as the PMMA/PC blend, but plain PMMA would likely break too easily in the torso of a humanoid. The PMMA/PC blend is simply what the folks at Trossen have been using for a while for all their Interbotix kits as it looks nicer than ABS and is safe/easy to lasercut like plain PMMA, but does not break quite as easily as plain PMMA because of the PC content. It does have some of polycarbonate's weakness to threadlocker (a variety of anaerobic adhesives), so have to minimize any contact just like the batch of styrene-rich Bioloid Premium frames that Robotis temporarily released several years ago before returning to a safer ABS-blend.
    Hi Tician,

    Thanks for your detailed reply. I originally plan to build another robot, so need to build my own skeleton. It seems that if I want to have customized parts of aluminum alloy or P95G, I would need a machine tool (not sure if this is the right word, but I mean a large machine to build the shapes). So maybe I should design by myself and send it to others to do outsourcing manufacturing?

    Shihui

  10. #10

    Re: The name of the material for HROS parts?

    If you have custom shapes, then it's usually better to design it yourself, and then either learn how to use the tools and rent them (many hacker spaces have laser cutters that can cut some kinds of plastic,) or 3d print them (in ABS or PLA) or send them out.

    To cut aluminum, the folks at Big Blue Saw are pretty good; they use waterjet cutting. They don't do bending, though, so if you need bending in the brackets you have to do that yourself.

    To cut plastic, and even thin stainless steel (16 gauge or thinner,) the folks at Pololu do a mail-in laser cutting service. Warning, though, that plain PMMA / Acrylic is too fragile (as tician says) and the "Plexiglas G P95" that is a little less brittle, is not easy to find in batches less than full sheets (32 square feet.)

    You can also send part files to Shapeways to be 3D printed in aluminum (expensive) or nylon plastic (which is very strong and nice for parts.) If you work in 3D CAD, this is often the easiest and least expensive way to go. It's still not "cheap" though, but a few hundred dollars will give you a complete smaller robot frame and it's very easy to work with.

    Finally, all of those pieces can be made in sheet metal, and there exists companies that take a project from drawings to completed parts (bent, tapped, anodized, whatever you want.) They do charge accordingly foir full service engineering. Try the folks at Rapid Sheet Metal / Rapid Manufacturing for example.

    Personally, I learned how to use the machines, got myself an affordable 3D printer, and go to a Tech Shop for using the laser, CNC, and waterjet cutting machines myself. Works great for me because this is a hobby, and I enjoy the making parts bit. Membership fees and safety class fees apply.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Choosing the right material for robot skeleton/chassis
    By PeterOeC in forum Mechanics / Construction
    Replies: 3
    Last Post: 02-20-2016, 07:41 PM
  2. HROS-1 Leaning Forward
    By ericshi in forum HR-OS1 Development and Discussion
    Replies: 9
    Last Post: 10-25-2015, 11:37 AM
  3. HROS-1 with ODROID XU4
    By LloydF in forum HR-OS1 Development and Discussion
    Replies: 7
    Last Post: 10-22-2015, 01:43 PM
  4. Project Beginnings of ROS on the HROS-1/Hello from University
    By Piper in forum HR-OS1 Development and Discussion
    Replies: 15
    Last Post: 07-07-2015, 02:43 PM
  5. Robotis brackets/parts as Inventor parts?
    By jwatte in forum Mechanics / Construction
    Replies: 0
    Last Post: 06-08-2015, 03:14 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •