Focus on Continuous Improvement

Continuous improvement activities are performed daily in all areas of the company. The activity selected to be highlighted for the month of September, 2019 is…

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Small Part Bending Part IV

Small Part Bending Part IV

In the final post of our Robotic Brake series we will take a quick look at the part chute and error checking plus a video of the overall cell functioning at speed.

We don’t want to have to open the robot cell door to remove parts and we’d like to limit human interaction with the robot. We came up with an idea for a dual chute system and sensors. The robot is programmed to put different part numbers into different chutes plus it checks to make sure a part is present before grabbing the next one in the tray just in case it dropped one or a part got stuck in a bending tool.

Two sensors mounted using 3D printed brackets at the entrance to each chute. The sensors are a double check that the robot successfully grabbed a part, bent it, and got it out of the tooling.

Two sensors mounted using 3D printed brackets at the entrance to each chute. The sensors are a double check that the robot successfully grabbed a part, bent it, and got it out of the tooling.

A sheet metal chute loads out into two different part bins.

A sheet metal chute loads out into two different part bins.

Small Part Bending Part III

In our 3rd part of our Robotic Brake series we are going to take a closer look at tooling.

We have standardized several different tooling sections so we are not swapping tools in and out which eliminates one possible source of error in bending accuracy.

You can see both standard Wilson Tooling and custom 3D printed tools using our incredible Markforged printers. The accuracy and repeatability are unmatched compared to our conventional brakes. The part edge does not touch a back-gauge so there is less error in positioning.

The robot is putting a part into the punch and die set for bending. The Wilson tooling is made at an angle that bending past 90 degrees is possible without changing to “stamping” in the tools.

The robot is putting a part into the punch and die set for bending. The Wilson tooling is made at an angle that bending past 90 degrees is possible without changing to “stamping” in the tools.

the drawing says 0.655” and it measures 0.6555”!! This may be a really good part for the picture but we haven’t seen a variance of more than 0.005 and less that 0.25 degrees between parts. On a side note, this is why we don’t use any paper drawings in the shop any more :)

the drawing says 0.655” and it measures 0.6555”!! This may be a really good part for the picture but we haven’t seen a variance of more than 0.005 and less that 0.25 degrees between parts. On a side note, this is why we don’t use any paper drawings in the shop any more :)

An example of an old steel die (with white protecting tape applied) for a specialty aluminum clip that we produce. This die would last 5000 parts before having to be re-machined into the proper size.

An example of an old steel die (with white protecting tape applied) for a specialty aluminum clip that we produce. This die would last 5000 parts before having to be re-machined into the proper size.

The aluminum clip still in the 3D printed tool set. Not only does this last longer than the steel die (about 10,000 parts) but it will not scratch as much.

The aluminum clip still in the 3D printed tool set. Not only does this last longer than the steel die (about 10,000 parts) but it will not scratch as much.

Small Part Bending Part II

Small Part Bending Part II

We made a post in December about our new advancements in small part bending. The idea was to offload high volume small bent parts so humans don’t have to stand in front of a machine for hours doing repetitive work. A lot of the small parts we bend require the operator to have their fingers close to the brake press tooling which over long runs of parts can be dangerous. We’ve made some huge leaps forward now that our robot/brake cell is in full production.

The robotic bending project is complicated enough that we will break the updates into several posts. This post will focus on part loading.

One of the first changes we made was blank holding. The flat parts are now put into a tray and loaded in a rack ready to be inserted into the robot cell safely from the outside. The trays allow the robot to know exactly where each part is and grab it. A macro written in the robot allows it to sequence across and then down through the different parts in the tray. The trays are precise enough that a “bad blank” cannot be loaded therefore checking the parts as the operators load them.

An empty tray ready to accept the flat blanks. These trays were put together in house using laser cut panels and 3D printed accessories.

An empty tray ready to accept the flat blanks. These trays were put together in house using laser cut panels and 3D printed accessories.

A rack to hold all of the trays. The top section contains different trays and the bottom stores completed parts in Kanban quantities for different customers.

A rack to hold all of the trays. The top section contains different trays and the bottom stores completed parts in Kanban quantities for different customers.

A tray loaded into the cell waiting for processing. The 3 sensors on the left allow the robot to detect which tray has been loading and automatically select which tooling to use.

A tray loaded into the cell waiting for processing. The 3 sensors on the left allow the robot to detect which tray has been loading and automatically select which tooling to use.

Summer Shutdown CI

Summer Shutdown CI

We’ve had a few questions from customers about what really happens during our summer shutdown: Is all of our equipment on the verge of breaking down and we need to repair it? I thought you guys had a good maintenance 5S system so how come you need to actually close the doors for a week? These are all great questions! Lean Machine does perform some maintenance off-hours (Sundays are usually free) but some projects are tough to complete in just one day. Here are some before and after pictures of the most visual part of our business.

This picture was taken a few hours before official shutdown began so some things like the people-lift wouldn’t normally be in the shop. You can clearly see how badly the floor paint has worn away.

This picture was taken a few hours before official shutdown began so some things like the people-lift wouldn’t normally be in the shop. You can clearly see how badly the floor paint has worn away.

Amazing! It took 3 days and 6 people to make this happen. Why do we want our floor painted when it would just be easier (and cheaper) to have it bare concrete? Better light reflection, easier to sweep, and it makes us feel happy.

Amazing! It took 3 days and 6 people to make this happen. Why do we want our floor painted when it would just be easier (and cheaper) to have it bare concrete? Better light reflection, easier to sweep, and it makes us feel happy.

Small Part Bending Automation

We have set out to build a robotic bending cell!  We did an analysis on all of our bent parts and a large percentage of them are small enough to be bent by a robot on a 4ft press brake.  Trying to be distruptive in manufacturing, we are stripping the brake of all controls and writing all of the logic into the robot controller.  As far as we know, no one has attempted to use a “dumb” brake in combination with a “smart” robot.  We found a “no name” press brake and we are using Motomans newest and best material handling robot.  We are at the very beginning of this project but wanted to share some progress of the cell coming alive.

One may ask the question; what does Lean Machine know about building equipment?  The answer is nothing!  We do know our own equipment well and it takes a lot of in-house technical knowledge to keep it performing at it’s peak. We also know how to integrate technology into our customer’s part manufacturing process and this project is an extension of that knowledge.  As with all projects at Lean Machine this is to give our customers a better price on parts with a higher level of quality!

This is the first part we want to bend.  It’s small so the operator has to over-ride the safety light curtain  on each hit which means the activation pedal gets hit twice per bend (4 times per part) which is brutal on an operator when a batch of 500 is the norm.   

This is the first part we want to bend.  It’s small so the operator has to over-ride the safety light curtain  on each hit which means the activation pedal gets hit twice per bend (4 times per part) which is brutal on an operator when a batch of 500 is the norm.

 

Here is an overall view of the robot and brake.  Lots of wires still hanging around during testing and start up. 

Here is an overall view of the robot and brake.  Lots of wires still hanging around during testing and start up. 

CUSTOM WORKHOLDING, COMPOSITE PRINTING

At Lean Machine we have recently added a Markforged Composite 3D printer, which has rapidly become a great new tool in our capabilities. Besides the ability to print strong mechanical composite parts for Jigs, Fixtures, Workholding, Tooling, R&D, and other applications, we have been able to make rapid progress in DFAM (Design For Additive Manufacture). We're discovering new opportunities and intricacies in this design process on a daily basis!

One of the greatest abilities of DFAM and Additive Manufacturing is to quickly solve emerging technical challenges around the shop, in an Agile fashion with minimal labour, at the very least without demanding the time of already busy machining centers and conventional production processes. When a new challenge developed on Extrusion processing on our new 5-Axis Gantry CNC, we had just the ticket to solve it...

Machine design complete with primary and secondary vises

Machine design complete with primary and secondary vises

Our initial configuration for workholding on this machine was based off a previously successful design on another machine, and further improved, consisting of quickly-moveable machine vises down the length of the table. This had proven very effective on the prior generation extrusion workcenter, and we took it a step further with higher quality, more rigid components to maximize the capabilities.

The challenge arose when we realized that to avoid machine collisions, the stickout of many workpieces was such that lighter cutting was required to achieve our standards of cut quality, so our Engineering team got to work on improvements to deliver greater performance. A new "Secondary" vise design was quickly developed in a matter of days, in fact designed entirely around the machine model, to bring the work holding as close to the end cut zones as possible.

The vise design in Autodesk Inventor

This new vise design incorporates Agile and DFAM design theories, and practical expertise from decades of Machining mastery. The choice to build many parts from purpose-engineered reinforced composites is no coincidence: These materials provide excellent dampening to vibrations from high RPM cutting, thereby delivering not only improved cut quality and speeds, but increased tool life as well.

The hard-working mechanical parts that give a vise its clamping capability are of course made from metal alloys, using almost entirely off-the-shelf components (McMaster-Carr in this case, ever-popular among Mech/Mfg Engineers thanks to one-day delivery). Roller thrust bearings, Steel and brass trapezoidal leadscrew components, and special hand-brakes for guideway mounting the vises bring the inner workings together. The vise bases are 5-axis machined in one operation on the same machine they are built for.

Various quick steps to take an Inventor part into Markforged Eiger, prior to printing

Over two dozen 3D printed composite parts are used in each vise, but most of these are small pressed in parts to reinforce fastening areas. The larger parts are reinforced as necessary with either high strength fiberglass, or continuous carbon fiber, in areas that require greater mechanical strength, undergo heavier compressive forces and other stress. Metal components and fasteners can be printed into the parts, or pressed in afterwards. Unlike machined metal parts, the printed parts take substantially less time to program than to design. Printing them can take a days for larger parts, but the process is unmanned and scrapped prints are extremely rare.

Assembly is a breeze, and the vises are ready for service! Thanks to the modular construction, any part that needs to be changed can be swapped on the fly, for example if a particular job requires a different jaw style.

Time to make some chips!