Bridging the gap between conveyors and forklifts.
Trends in lean manufacturing and safety legislation have led to gross inefficiencies when moving heavy stock between workstations. Advanced factories custom engineer dollies and cranes, however smaller facilities are limited to existing, often unsuitable solutions.
Make work safer and smarter.
A unique combination of springs and smart actuators keeps the top layer at the perfect loading height, throughout stacking, reducing operator lifting and bending. Rather than interrupting the work flow to manually set the height for each layer, Stack-Lift automatically finds the right height based on previous use patterns - combined with unmatched mobility, reducing the need for forklifting and a battery life in the weeks rather than hours. The Stack-Lift's infinitely expandable digital platform will prove a powerful tool for increasingly data driven factory mechanisation and optimisation.
Designing for People
The most vital step of the design process is ensuring you understand the need, for every stakeholder.
Before resolving any details we travelled to timber mills and processing factories in China and throughout Australia to research use patterns, compare stock systems and interview workers, managers and owners.
After experiencing the problem first hand, then exploring market potential and encouragement from investors vaupel set out to define the problem and profitability of a solution to stacking and moving heavy stock. Focus was on the timber industry due to the primary client's needs, but all solutions must be applicable to material handling in general.
Across very varied systems and attitudes, there is an unwavering need for flexibility, ease of use and integration into existing processes. Improving OH&S and efficiency are seen as vital, but should not interfere with existing daily operations.
To purpose of this project is to create the best solution for the primary client Vic's Timber, while also designing a product for a wide variety of facilities with similar needs. A solution which suits many other related applications is better for a dyamic factory, and also substantially reduces the end unit cost
by increasing the production volume.
Universal: Existing processes such as forklifts, pallets conveyors and equipment must be compatible with the Stack-Lift's intended use. Tight spaces, rough ground, long stock lengths, unpredictable scheduling, low-skilled workers, basic infrastructure and differing work culture should not reduce the solution's relevance.
Safety: Safe operation of the Stack-Lift, including ergonomics, movement, maintenance and new users is critical, in addition to the OH&S considerations of lifting, bending and twisting from the handling process.
Automatic: The top layer of a stack must be kept at the exact right height, without needing precise controls, manual lifting or any modification when changing which material is being stacked.
Mobile: The whole device, loaded with stock must be easily moved to the next station. optional motorised assistance and load covering may increase efficiency and reduce risks. The device must move freely in all directions, through tight spaces and be lockable.
Uninterrupted: Work must not be constrained to power outlets or be interrupted by charging cycles. When stock changes there must be no lengthy modification or programming required.
Convenient: Storage when not in use, maintenance, training, upgrading and customising - as well as the purchase and support process should be straightforward and well considered.
Economic: For a business to justify the cost of purchase and operation, the financial impact made by labour, speed, insurance, sick leave, and operational improvements must quickly recover the initial outlay. Return on investment time frames vary greatly, however a short, quantifiable R.O.I will make the decision to implement Stack-Lifts clear.
Design for Lean Manufacturing: The solution must be manufacturable in small quantities at low cost, using common techniques and existing proven components. This will reduce the cost and allow for continual improvement of the product, manufacturing process and business supply model.
A universal tool
Stack-Lift is a non prescriptive design, that can benefit any existing system.
- It works with forklifts by incorporating slots for the tines and can be accessed from any side.
- The entire footprint is within a 1200 by 1200mm pallets, meaning it is compatible with racking and other space critical situations - particularly when compared to a forklift.
- Folding arms allow one unit to service big and small materials with a 2 second change over
- By using standard parts and opensource computing every feature is easily customisable.
Common modifications may include adding more actuators and springs, removing or enlarging the wheels, adding batteries or integrating more computer hardware and software for smart factories.
Instead of prescribing a specific use, Stack-Lift works with any material, any where, from any side
The importance of workplace safety and reduced strain are becoming increasingly important and mandated by regulation, however there is a strong sentiment in many workplaces that over regulation erodes 'common sense' and many requirements cause more problems than they solve.
The Stack-Lift must immediately be a more appealing solution;
making the task at hand easier, as well as safer.
- By making the use of a scissor lift easier, as well as safer, the worker is much more likely to use a mechanical aid, as prescribed by regulation.
- Every detail has been designed for ergonomics: the handle can be used with one or two hands to prevent bending and pushing, the battery rises to a safe height for removal, the arms fold out from one side to reduce bending for the operator and all regular controls are done by foot, because even remote controls often require bending based on where they can be secured.
- By taking every item to the exact height, not just close, the operator can slide rather than lift .
- A quick release ratchet strap in the centre reduces the risk of timber falling when the Stack-Lift is moved.
- By clearly displaying information on a large screen - the operator is always aware of the machines status and next actions. The actuators are default safe, as is the relay circuitry.
No learning curve
The bright 125mm screen simply shows how the Stack-Lift learns a pattern and where it will go next.
The operator drives the stage up or down once, after which the Stack-Lift learns the pattern and repeats the distance when the repeat button is pushed. The touch screen allows the operator to engage more deeply with the system if needed - easily programming time based movement, syncing with other machines or data mining to increase efficiency.
Simple comments are displayed on the screen for first time users, such as "press the foot pedal up to begin". Warnings, status and any required attention such as charging, is explained in plain English with audible communication optional.
By using one or more powerful springs, the Stack-Lift consumes very little electricity when used in a loading and unloading cycle. The actuators only draw as much power as the difference between the spring's power and the load's weight.The 24V 4ah Gel battery can be safely swapped by one person in under a minute, as it is located at waist height (when raised) and features an ergonomic handle and power drill style swap clip.
For occasions where the stacklift is not expected to be moved it features an on board power supply and charging unit with a 15m retracting cord.
Folds away for storage
Unlike almost any other scissor lift, The stacklift shrinks to just 23cm off the ground and the size of a pallette. The handle can easily be used to tilt the whole unit on its side for transport and efficient storage when not in use.
The open-source software and hardware can easily be modified to be triggered by time or other sensors to fully automate some or all of the process. With the current design this requires a basic understanding of C++ but in the future vaupel would like to offer plug and play additions such as height sensor, wireless triggers and synchronisation with other stack-lifts.
By collecting more data, such as through-put speed and times of inactivity; managers can compare and optimise methods for stock handling. The exact use of the data will vary factory to factory, however it will always provide a valuable insight and powerful new suite of tools.
That was the main message from Keith Nosbusch, CEO of Rockwell Automation, which cosponsored a CEO roundtable discussion at the Smart Manufacturing Summit. Nosbusch was one of the key executives that spoke at the summit, which included Ford Motor Company, Caterpillar and others. Nosbusch stressed that real-time feedback from the consumer will allow manufacturers to apply that information quickly on the plant floor to change what they’re making.“That seamless integration of the enterprise, the supply chain and the plant floor is becoming the next wave of competitive differentiation,” he said.
The Design Process
concept generation and mapping
To ensure no potential option is neglected and no flawed option is pursued unnecessarily, each option is placed into an options matrix and trough research, testing and continued resolving of each component, the best option is selected for each category.
As the design process progresses, options are changed, culled and added to. Fast prototyping and a flexible schedule ensure no chance for improvement is ignored, even if this adds time and complexity to the design process. If testing is left too late, an almost complete design may have to be scrapped because it's failure wasn't detected quickly enough.
Build Early, Build Often
To test each design aspect in context, increasingly resolved sketch models, tests and full prototypes were constructed and modified. This testing based method of prototyping produced many valuable results and ensured the design was suitable for small scale manufacturing before committing to bulk orders - a key requirement of the brief and start-up business model.
The first complete prototype was presented at UTS in November 2014,
only 9 months after the problem area was first explored.
User testing confirms the need and uncovers weaknesses
Evaluation and testing of the first full prototype revealed valuable information about the refinements needed to create the best solution. User feedback, based on a physical prototype proved much more detailed, and more critical compared to interviews conducted verbally or with drawings.
The User Scenario, and fundamental needs such as repetitions, ergonomic access and simplicity were confirmed. Most importantly the market gap and user interest confirm the value of the desired solution.
Integration with existing systems, such as forklifts and pre-installed machinery were a lauded design goal and must be kept as a high priority as the design is refined and improved. The lowered slots for forklift tines were however recommended to be further apart to prevent the operator from needing to adjust the tine width.
Foot pedal operation, rather than hand buttons, were seen as a valuable feature reducing bending and interruptions when accessing a wired remote controller.
Simplifying the lifting mechanism is vital to create a functional, reliable machine. Although extremely efficient in theory, practice showed the sacrifices needed to control a purely spring based adjustment system are not feasible in this application.
Size Reduction would allow for use in a wider range of facilities, as many factories and warehouses have narrow spaces in which the full 2m length would be cumbersome.
Clearer operating procedure is needed to initiate users, workers and buyers. Although the adjustment function described above is basic, it is not intuitive or immediately understandable.
A handle, and means for securing the load would define the Stack-Lift as a stock movement device, in addition to it's lifting function.
Design Phase 2
The above findings were evaluated and compared to the design scope in order to update the brief.
Acting on the findings of phase 1, ideation and modelling of a new frame, lifting mechanism and added features was carried out over a period of 3 months. To arrive at the final design, all methods of lifting, controlling and building were considered.
A Solidworks sketch, part or assembly was created to test every option
Power over Springs
To overcome the linearity problem of the first design, electric actuators were found to be a reliable and cost effective way to control the hight, while one or more powerful springs store the bulk of potential energy to reduce electricity consumption. A digital control mechanism was designed using c++ and opensource hardware to allow future modification.
The frame has been changed and adjusted throughout the design process. To increase prototyping speed a smaller gauge and wall thickness has been used. This demonstrates weak points, allowing them to be reinforced - rather than wasting resources by over engineering every component. Before mass production and certification can be achieved, each component will need to be designed and tested to withstand full operating stress with a high safety tolerance.
Progress Report: week 10
Throughout the design process quick reports were recorded and shared with my masters supervisor to show progress and garner feedback.
A rotary encoder, with hardware de-bounce circuit is fitted inside a low cost 8000N actuator to measure the height within 100um, while an ATMEGA micro controller learns the users requirements and sets a target height. A single momentary foot switch sends the stage to the target height when desired. A Picaso based intelligent resistive touch screen, with on board graphics processing, displays the user interface with icons, clear text and conditional instructions. Audio feedback with optional voice guidance and loudspeaker provide non visual feedback to the user whilst in operation.
Power management is done by 20A mosfets switching 40A coil relays to isolate the 5v control circuit from the 24v actuator wiring.
Onboard smart chargers can charge and maintain the 4 12v, 2.2a SLA batteries using a retractable 15m extension lead, or the batteries can be swapped out in seconds using a fixed charging doc with multiple batteries kept ready.
The graphic user interface consist of a main page showing the current height, previous height, next height and repeat distance. A large icon clearly shows the direction in which the stage will move when activated. A battery icon shows charge percentage, while other screens allow for calibration and settings adjustment.
Phase 2 conclusions
It's a winner
User feedback from the phase 2 prototype was extremely positive, culminating in a request to purchase 3 units, provided the cost could be kept close to $1000 per unit and key outcomes met. These focused on:
Make it stronger
Increasing the operating load to 2000Kg. Due to the ability to add many more actuators this is well within the capability of the design. The scissor arms will be altered back to the original wall thickness as is required, the form factor and mechanism need not be changed.
Keep it customisable
Between the first and second user tests this particular mill's requirement had changed and wheels were no longer deemed necessary. While this is a key feature for other mills, this change in need highlights the need for a modular design, easily customisable for differing scenarios.
The minimum height was desired to be lower - achievable be removing the wheels - and the incorporation of taller tine slots would prevent the need to add gluts, further reducing the minimum height.
The bottom line
Each feature must be worth it's cost, and the total unit price remain below $1500. Further feedback included suggestions that in this particular scenario batteries were not required as mains power was easily available. However a retracting cord, and the option of occasional battery power was considered beneficial - provided it did not substantially increase the cost.
This design process has been undertaken as part of Karl Vaupel's Masters Of Design at the University Of Technology, Sydney.
I sincerely thank my mentor Shelden Vaughan for his steady guidance and commitment to the outcome, Danon Bradford, without whom my code would not compile and Ayca Ipekcan, my unstoppable partner, who had my back from day one.
Releasing the Stack-Lift to market will require a partnership or acquisition. Vaupel Design is seeking a partner in a joint venture manufacture and distribution deal; or to sell the IP, drawings, prototypes and all findings to a manufacturer. Altering the final prototype for manufacture will require each component be optimised to suit the machinery and manufacturing processes available. The first 3 to be delivered to the primary client can be fabricated manually in Australia, acting as a beta test to oversee quality and collect extended use data. Upon delivery and longer term feedback from the client, vaupel Design will aim to sell or partner with an existing manufacturer/distributor capable of reaching a large international market.
Specific elements which require refinement before production are:
- optimisation of code and electronics to reduce standby power consumption and physical size
- expansion of the interface to include detailed introductory instructions and customisation settings
- use of long life bearings in critical joins and durability testing all components
- selection of steel grade and section to achieve maximum strength whilst reducing fabrication cost
- user testing and feedback from a wider variety of potential clients
- development of a lean customisation process ensuring only the required features are included whilst increasing the breadth of potential uses.