Sites: GlobalSpec.com | GlobalSpec Electronics | CR4 | Electronics360
Login | Register
The Engineer's Place for News and Discussion®

Previous in Forum: Power of motor?   Next in Forum: Two Fire Pump In Series
Close

Comments Format:






Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







9 comments
Participant

Join Date: Nov 2007
Posts: 3

Design For Robotic Assembly?

11/27/2007 3:00 AM

How do we start to design for robotic assembly

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".
3
Power-User
Engineering Fields - Mechanical Engineering - By Degree Engineering Fields - Manufacturing Engineering - By Profession Popular Science - Weaponology - By Interest United States - Member - Member Since My Inception

Join Date: May 2007
Location: Florida
Posts: 154
Good Answers: 5
#1

Re: Design for robotic assembly?

11/27/2007 7:57 AM

Three factors determine how easy it is to use an assembly robot for a product. Each product part should be examined with respect to these three important qualities. In order of priority, they are the; necessity of the part to be separate from those which have already been assembled; ease with which the part can be handled, and the ease with which the part can be inserted. By considering these factors in turn, the most economical design of product can be chosen for robot assembly. A measure of the assemble-ability of the product is the 'design efficiency', and this is related to the above factors.

A part is considered to be necessarily separate from those previously assembled if one of four conditions apply to the part. Otherwise, it can be eliminated. Firstly, if the part or sub-assembly moves relative to its mating part during the normal function of the final assembly then it must be a separate part. Secondly, if the part or sub-assembly must be of a different material than its mating part (eg. for insulation, vibration damping) then it must be a separate part. Thirdly, if disassembly of the part or sub-assembly must be allowed for (e.g. servicing requirements, recycling) then it must be a separate part. Finally, if the part or sub-assembly, when combined with it's mating part, would prevent the assembly of other separate parts (except where the part's only function is to fasten) then it must be a separate part.

The majority of insertion processes take place along, or about, the vertical axis. If the action of insertion for a part is not in the vertical axis then the process should be analysed to see if the more complex insertion path is really necessary. If possible, it should be re-designed to take place in only one axis. The vertical axis is always the preferred axis because the weight the part acts in this direction and assists, not hinders, the operation. The robot cost is lower if insertion processes are kept simple. This is because complex operations need more robot degrees of freedom and each degree of freedom requires an individual pneumatic, hydraulic or DC servo motor which increases the cost of the equipment. Additionally, the potential profitability of the equipment is reduced because the cycle time of the operation will also be increased.

__________________
Light travels faster than sound. That's why some people appear bright until you hear them speak.
Register to Reply Good Answer (Score 3)
Participant

Join Date: Nov 2007
Posts: 3
#5
In reply to #1

Re: Design for robotic assembly?

11/29/2007 2:48 AM

Thank you for your comments they will be a very useful starting blocks in my future design efforts.

Register to Reply
Associate

Join Date: Sep 2006
Location: San Diego
Posts: 28
#2

Re: Design For Robotic Assembly?

11/27/2007 11:23 PM

try this website www.Parallax.com They sell great literature and hardware kits for robotics applications. I used most of their material while I was taking a robotics course. Their prices are very reasonable. Good Luck

Register to Reply
Active Contributor

Join Date: Nov 2007
Posts: 22
#3

Re: Design For Robotic Assembly?

11/28/2007 7:24 AM

You can obtain software to simulate the robotic functions. One source would be ABB's Robot Studio.

Register to Reply
3
Power-User

Join Date: Apr 2007
Location: Kingman, AZ
Posts: 111
Good Answers: 3
#4

Re: Design For Robotic Assembly?

11/28/2007 11:35 AM

At the design stage, the best thing you can do if there is thought of using automation, is to look at the individual components of your product and how they will be assembled. Look for orientation issues, such as circular type components that might have difficulty in being presented the same way each time when placed into position for assembly. Providing keying features can greatly assist down the road if automation is chosen. This can save you from having to purchace a vision system for a specific operation, by allowing you to mechanically guide the piece into position.

If you have noticed, I avoid the using robotic because of what it envisions in others. A gantry style robot can be as simple 3 programmable linear sliders mounted overhead on the X,Y, & Z axis programmed to dispense adhesive in a pre-determined pattern.

The smartest thing you can do as a designer is to work with manufacturing upfront in making your design manufacturable.

Register to Reply Good Answer (Score 3)
Power-User

Join Date: Dec 2007
Location: Franklin, NC
Posts: 111
Good Answers: 5
#6

Re: Design For Robotic Assembly?

12/09/2007 7:42 PM

And don't let someone sell you a robot if a pick and place machine will do the job.

__________________
Peace be upon you.
Register to Reply
Power-User
Engineering Fields - Mechanical Engineering - By Degree Engineering Fields - Manufacturing Engineering - By Profession Popular Science - Weaponology - By Interest United States - Member - Member Since My Inception

Join Date: May 2007
Location: Florida
Posts: 154
Good Answers: 5
#7
In reply to #6

Re: Design For Robotic Assembly?

12/09/2007 11:18 PM

I concurr. Make sure you understand your application FULLY. Do not use a robot just to satisfy someone elses suggestion. Especially if the task you are looking to automate is simple, there are simple pick and place units that are releatively easy to mount and program. If you go to a robot supplier, they will want to sell you a robot, or 2 or 3... .

__________________
Light travels faster than sound. That's why some people appear bright until you hear them speak.
Register to Reply
Participant

Join Date: Nov 2007
Posts: 3
#8
In reply to #7

Re: Design For Robotic Assembly?

12/11/2007 1:18 PM

I'd like to say a big thanks to all of you for the comments and info.

Just to add another perspective to this entire automation principal. What if I don't have an application yet? My interest is in using automation on small batch production within the company.

This means that a justification will not be carried by one project. I'm looking to justify that automation can be has versatile as conventional production processes.

I think this means I need to use a robot. For example I would expect it to produce say 1000 sub-assemblies of product "A" Monday to Wednesday and change it over to product "B" to run for the next two weeks. Then find that we need 1200 items of product "C" urgently before product "B" is complete.

Question – Am I expectation too much?

Register to Reply
2
Power-User

Join Date: Apr 2007
Location: Kingman, AZ
Posts: 111
Good Answers: 3
#9
In reply to #8

Re: Design For Robotic Assembly?

12/11/2007 2:09 PM

Whether you have a high volume single product production line vs. a small volume/customer flexible multi-product process doesn't change the dynamics of whether you need a 6-axis robot vs. an automated station. But why spend $25k to $50k on a 6-axis robot if 3-axis can accomplish the required task for much less money.

If you can arrange your process so that the robot can perform, say 2 or 3 operations, while maintaining a balanced work flow then go for it. But if all you are trying to do is perform a single operation within the process flow it is totally unnessary.

There is no more advantage to using a robot vs. using programmable linear sliders mounted to create a 3-axis gantry-style 'robot' on a flexible (multi-product) production line. What is require for a flexible line is not the robot, but in design of your pallets that will carry your product and the manipulators that will carry out the work. If properly designed for quick change-out you can adapt to families of products quite quickly.

Example:

At my last company, we had high volume automotive product production lines and we also had low volume Industrial where we had over 120 different customers ordering anywhere from 100 to 50k/year. Our existing testing station required various pressure manifolds and cable harnesses to handle the numerous pressure ports and connector configurations. This caused various headaches such as maintenance of connector cables, wasted space for storing the fixturing, losing throughput due to testing 6 at a time and having a leak on one or operator aborts test due to 1 failure, etc.

I solved this by creating a matrix of all the connector, port, and stack up variations, to develop a 2 part test station where the operator could test 1 part, while loading the second and alternate between the 2. Instead of threading into a port, I created family of nests and connector plugs and used air cylinders to hold 'test package' in place for any pressure from 0.5psi to 750psi.

My point is, take the time in small batches to find similarities between products and create fixturing designed for quick changeout and maintain your throughtput by accomplishing various tasks in parallel when possible. In this particular function, could I replaced the person with a robot? Probably, but with the person, as long as I empower them, I have someone who can quickly adapt to changes in my process, whereas with the robot is only as smart as the person who programmed it, thus rarely adapts easily to unexpected changes in the process.

Register to Reply Good Answer (Score 2)
Register to Reply 9 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".
Copy to Clipboard

Users who posted comments:

All About M.E. (2); Fluids guy (1); reygalindo (1); rjg@scancoin.com (2); Skelley (1); Sonave Sunsets (2)

Previous in Forum: Power of motor?   Next in Forum: Two Fire Pump In Series
You might be interested in: Robotic Tool Changers, Robotic Deburring Tools