Shop Performance: Maximizing your Shop Performance

May 30, 2013

Head Shot

I have written about the benefits of manufacturing solutions based on nesting (see March/April issue) and sawing (see July/August issue) systems. In this article I will compare both and help you decide which one may be the right solution for your shop. If you expect a clear vote for one or the other, you will be disappointed. However, after you have read this article, you will be able to determine for yourself, which is the right system for your production.

Both systems have their strengths and weaknesses, and this article will explain the main arguments.

Capacity

The capacity of both cutting solutions is affected by the cutting pattern, the board size, the cutting speed and the book height (meaning the number of boards that can be cut at the same time). For cabinet parts or similar components you can expect to process approx. 50 boards per eight (8) hour shift and increase to 80 sheets with the right automation. A panel saw can process substantially more panels. Even the smallest beam saw can cut 100 single panels (no book cutting) per shift and an angular plant will cut up to 1,500 panels in a single shift.

Space

An entry level-nesting machine will require a minimum of 200 ft., 10% less floor space than a panel saw. You have to add at least 50 ft. for a CNC drilling center to the saw solution to drill and route the parts the same as a nesting machine. Once you are considering a nesting solution with automatic outfeed to increase capacity, the space difference becomes insignificant. If you need more than one nesting machine to meet your production, a panel saw with a CNC drill will become the less space demanding solution.

Investment     Costs-associated-with-equipment-downtime

You can purchase an entry-level nesting machine as well as starter panel saw for about $70,000. Once you consider automatic off-loading for your nesting machine you can easily double that investment. This would then cover the cost of the additional CNC drill required for the solution with a panel saw. For larger production capacities where multiple nesting machines would be required, a panel saw solution with a CNC machine is, in most cases, more cost effective.

Automation

A wide range of automation solutions is available for these technologies. The first to be considered is typically part labeling, which is easier to implement on a saw; in the most basic version you already deal with one part at a time, which makes labeling easy. On a nesting machine you have to either put the labels on the full sheet prior to cutting (when their position is difficult to determine) or you have to apply the labels after the parts are cut. Any good labeling solution on a nesting machine requires some sort of automation.

LabourPerson hold spanner

A nesting solution is typically designed for a single operator; whereas a panel saw solution with a CNC drill that is run at capacity will require two operators. The processing cycle on a nesting machine is relatively long, which allows the operator to complete other tasks, such as horizontally drilling and doweling fixed shelves.

Capability

In general the saw/CNC combination offers a higher capability than a nesting machine. A panel saw in combination with a CNC router gives the operator a vast array of materials, porous and non-porous, that he can cut and process. Furthermore, this type of system offers greater processing options, i.e. grooving, four-side processing, postforming cuts, stress release cuts or the cut of strips for your edgebander (laminate or solid wood).

Production costs

Apart from the labour cost, which can be offset by the difference in production capacity, the two systems show a significant variation in production costs. The tooling costs and energy consumption for the nesting system is at least 50 per cent higher per part than for a panel saw solution. The nesting process removes at least twice as much material to separate the parts. This also increases the dust collection requirements; and the need for all parts to be held down continuously by vacuum during the nesting process, requires a much larger vacuum system than a CNC router. A nesting solution also requires the periodic machining and replacement of the spoil board.

Material  A1 - Edgebanding

Both systems handle laminated particleboard or MDF very well, since these are virtually airtight and allow a good hold with the vacuum system on a nesting table. Once the materials get more porous or have a somewhat uneven surface (very open grain veneer, ply- wood etc.), it becomes more and more difficult for the vacuum system to hold the materials, whereas the mechanical hold-down by the pressure beam of the panel saw is not affected at all. Small parts or corrugated panel will also create problems on a nesting system.

Production concept

The single biggest advantage of the nesting solution is the fact that it cuts and drills parts in one step and eliminates the handling required between the panel saw and the CNC drill, but this comes at the expense of production capacity. By combining two production steps into one production cycle one loses the capability of parallel processing and therefore a shorter production cycle.

Yield

Yield is an important factor and the main reason for the development of the nesting solution, which was originally developed in the textile industry. There is a 20 per cent yield improvement when taking the same round component and processing it with straight cuts or ‘nesting’ it into the same sheet.

The more rectangular parts you have in your production, the less significant the difference will be. Another factor influencing the material yield is the waste due to the actual cutting path. A typical saw blade thickness is 5 mm or less, which accounts for a waste factor of approximately 2 per cent with average cutting patterns. The waste when using a nesting machine depends on the diameter of the router bit. Most common are router bits of 3/8″ or 1⁄2″, which reduces the yield by about 4 per cent.

Software    WoodWop-A1

Both machine concepts require software to run most efficiently. The nesting solution requires the cutting and drilling information to be combined in order to generate a nesting pattern for each individual order. The part sizes are determined when the designer specifies the layout with the consumer and the drilling patterns are assigned according to the rules specified when the design and manufacturing software was originally set up. The panel saw solution could be set up in a similar fashion by sending cutting patterns to the saw and individual drilling patterns to the CNC drill, which are called up manually or by barcode. A more common set-up is sending the optimized cutting patterns to the saw and maintaining the drilling patterns separately. Drilling programs are called up manually or via barcode, but they can still be adjusted through variables on the plant floor if necessary.

Form and size of parts

The panel saw with a CNC router has the least restrictions in regard to the shape, form or size of components and you can virtually duplicate any operation on the part that you can do manually. This can also be done on a nesting machine, but will require considerably more effort for setup and specialized hold-downs. However, most non-rectangular shapes will have a higher yield, if processed by a nesting machine (see criteria yield), but smaller parts are better cut on a panel saw.

As you can see from the above overview there is no easy answer as to which production solution is right for you. As a general rule we can say that a small cabinet shop will benefit from a nesting solution because it will require less space, less labour and the lowest investment. As production requirements increase things are much less clear-cut, but as volume goes up, the unit production costs go down with a panel saw and CNC drilling solution. To find out the right production concept for you, you have to carefully evaluate each of the above aspects to determine their importance in your particular case. For example you can create a list and rate each aspect one by one. If the nesting concept is advantageous mark “N” behind the criteria, if nesting is very beneficial note “NN”. If the saw/ drill combination is more favorable put “S” or “SS” behind the criteria. If both concepts have the same value, mark the criteria with “0”. When you have marked all criteria count the “N” and “S”. “SS” or “NN” count double. The process with more counts will be more likely to fit your requirements. This is of course only a very rough guideline. Please talk to your consultant or machine supplier for a more detailed evaluation.

As a final point, keep in mind that ‘today’s’ nesting machine can also become ‘tomorrow’s’ CNC machine in a saw/router solution.


Shop Performance: Maximizing your Saw Performance

May 23, 2013

Head Shot

Does the automatic panel saw still have a place in today’s woodworking shop? There is a perception that panel saws are only useful for high-volume production and that the better way to handle today’s just-in-time manufacturing is with a nesting router that handles one sheet at a time (see my article in the March/ April issue). However, even production shops with 30-40 boards per day can benefit from a panel saw. They provide quick cutting capacity, produce a crisp clean cut without pulling fibers out of the edge for application of even the thinnest edge tape and they have lower energy consumption and longer tool life.

When looking for a new panel saw the capacity of the machine is an important factor. The machine has to match to your current requirements and allow for future growth as well as manufacturing flexibility. In this article I want to guide you through the question of ‘what is the right size saw.’

It is a common belief that saws with a bigger cutting height always provide a higher cutting capacity. This is wrong. A bigger cutting height will increase the productivity only if you can cut books. Today’s trend to smaller batch sizes and just-in-time production has meant that most saws are cutting only one or two sheets high on average. In today’s production shops a big cutting height is only necessary when you have to cut boards or components that actually are 100 or 120 mm thick, like you would find in the plastics industry or in special applications.

The speed of a saw is another measure that is often used to gauge saw capacity. It refers to the maximum speed that the saw carriage can travel. Some saws show peak speeds above 200 m/min, but that doesn’t mean you can cut at that speed. Most common saw blades allow you to cut with a speed between 40-60 m/min and produce a clean cut. Only with special tooling is it possible to cut chip-free up to 150 m/min or more. Nevertheless, due to the acceleration and deceleration of the saw carriage maximum speeds will only be reached for very brief periods of time. Actual cutting speeds also depend on how many boards are cut at the same time. A single sheet can be cut faster than a book of four. The panel saw should identify the book height and adjust its cutting speed accordingly.


To demonstrate what capacity differences exist between seemingly equivalent saws, have a look at a typical cutting pattern that was pro- vided by a customer. The panel size is 2800 x 2070 mm and cutting speed 50 m/min.

The pattern was cut on one saw in 3 min. 34 sec, while a comparable saw only required 2 min. 48 sec. A substantial, 27 per cent capacity increase.

 

To answer the question what really determines the cutting capacity of a saw we have to analyze the process. There are many factors, each of which has an influence on the final outcome. In the graphic below we divided the cutting time for one complete pattern into five groupings:

As expected, the cutting cycle takes up the largest chunk of time and is mainly determined by the maximum cutting speed allowed for the material to be cut. What is unexpected are the large time segments devoted to the pressure beam movement, the positioning and the alignment cycles. For this chart we used a ‘smart pressure beam,’ which means the beam only lifts up 30 mm between cuts, instead of going all the way up every time. A regular pressure beam that moves all the way up and down for every cut extends the overall cutting time by 26 seconds or in other words, wastes 18 per cent of capacity.

Just as in the automobile industry, which established standards for fuel consumption, there is an accepted ’Triple Mix’ standard in the wood- working industry that allows you to accurately gauge cutting capacity based on many of these factors, not just cutting height and saw carriage speed. The ‘Triple Mix’ is based on three typical checkerboards, staggered and head-cut patterns. You have to also consider many optional features like Power Concept or Twin Pusher or X-Y Systems that influence the final throughput.

The only way to properly evaluate a panel saw is by actually running cutting patterns on the different saws you are considering and then compare their performance. If you would like to receive a copy of the ‘Triple Mix’ standard please email me at Christian.Vollmers@homag-canada.ca and I will send you a copy.


Innovation of the year at the LIGNA 2013

May 21, 2013

powerTouch – a whole new dimension in machine operation

_______________________________________________________________________

Second highest trade fair order intake ever recorded over the company’s history

Appearing once again as the biggest exhibitor at the world’s leading fair for the woodworking industry and woodworking shops, the HOMAG Group’s presentation at this year’s LIGNA was a resounding success. Encompassing a total area of almost 7,000 square meters, HOMAG City proved the pivotal attraction of the show. After five busy days of rewarding and interesting shop talk and in-depth dialog with new and existing customers, the HOMAG Group returned triumphant with the second best haul of orders ever closed at a trade fair, falling just short of the record-breaking 2011 result.

Touch the innovation – touch the future

No other trade fair catering to the woodworking industry can boast such a high innovation density as the LIGNA. The new powerTouch system from the HOMAG Group was undoubtedly the innovation of the fair. This pioneering new touchscreen operating concept combines design with function, combining with the powerControl system to provide the ultimate in customer benefit: Simple, standardized, ergonomic, evolutionary. The focal feature of the system is a large full HD multitouch monitor in wide-screen format, at which machine functions are controlled by direct touch contact. Standardized operating elements and software modules ensure that all the HOMAG Group machines can be operated with the same look and feel using the new concept.

20 world innovations live

The legendary InnovationCenter located right at the heart of “HOMAG City” met with an equally enthusiastic reception. Safely concealed in the Center and accessible only to selected representatives of the trade public, 20 units were on display, featuring an array of technical highlights and new process technologies to enhance quality, flexibility, productivity and cost efficiency. These include realityPlus – the virtual machine. With this ground-breaking development, the HOMAG Group led the field as the industry’s first manufacturer to enter the world of virtual reality. With realityPlus, the HOMAG Group has succeeded in linking the real environment to the virtual world, so securing a decisive technological leading edge – and allowing its customers to benefit from more security, more performance and higher efficiency.

Megatrends: Zero joint & batch size 1 plants

One of the focal themes of this year’s exhibition was the zero joint. Customer expectations of ever higher processing quality with the disappearance of visible joints continue to grow. Alongside office and bathroom furniture manufacturers, fitted kitchen firms are also focussing their attention on the laserTec method with feed rates of up to 52 m/min[1]. The figures speak for themselves, with over 200 HOMAG laserTec units sold since 2008.
“Using laserTec from HOMAG, which we are deploying with a high level of success in three performance categories, we are able to offer industrially-oriented customers a method which allows them to combine zero joint manufacture with extremely high levels of productivity and flexibility with high volume output. Our product spectrum is rounded off by BRANDT airTec for lower feed rates from 15 m/min1. Medium-sized companies benefit in this situation from an ideal solution package affording them entry into the world of zero joint technology – with almost identical results in terms of quality and appearance. With airTec and laserTec, the HOMAG Group provides its customers with a chance to achieve an invaluable edge in terms of enhanced quality in performance category, making them ideally equipped to meet future challenges”, explains Dr. Christian Compera, Director of Research & Development at HOMAG Holzbearbeitungssysteme GmbH.

A series of individually linked high-tech machines covering the entire process chain were also featured at the LIGNA, providing irrefutable evidence of the HOMAG Group’s standing as the premier specialist in individual plant engineering for modern furniture production. The spectrum of machines on show in HOMAG City ranged from storage systems through sizing and nesting technology, order picking and sorting to drilling, assembly, hardware mounting and packaging.

Detailed descriptions of all innovations are provided in our press folder.

Achieving sustainability with “ecoPlus” and “HOMAG Cares”

Energy, time, material and personnel – HOMAG Group customers are offered ways of saving all of these precious resources by using ecoPlus technologies. ecoPlus encompasses wide-ranging developments and technologies permitting up to 30% energy savings and sustainably reduced operating costs. Using ecoPlus facilities such as the standby mode, optimum extraction or controlled compressed air consumption, HOMAG Group customers can save up to 80,000 tons of carbon emissions every year. At the same time, the system makes for more productive operation with over 100 different measures.

Actions speak louder than words: Under the “HOMAG Cares” banner, once again the HOMAG Group donated the proceeds from sale of the demonstration parts to charity. At the LIGNA, the 2,000 Euro donation was presented to two charitable institutions in North Rhine Westphalia: the Bethel Children’s Hospice and the “Unser Haus” scheme for the disabled. The Bethel Children’s Hospice in Bielefeld is one of eleven hospices throughout Germany which specializes in the care of terminally ill children and their families. The “Unser Haus” scheme has provided care, aid and support for people of all ages with disabilities for the past 20 years. Alongside in-patient and out-patient care, residents are offered a comprehensive support and activity program.

… and action! Experience the LIGNA online

A number of film teams were also present at the show to interview fair-goers and record the mood. All the interviews and trade fair highlights are available to view at http://www.homag-group.com/ligna or www.youtube.com/homaggroup.

Visitors from Mauritius to Greenland

Over 90,000 visitors from around 100 countries made the journey to Hanover. The mood inside HOMAG City was buzzing with excitement and enthusiasm. Of those who visited the HOMAG Group trade fair stand, around 56% were from outside of Germany – a higher proportion than at the last LIGNA. Alongside Russia and Poland, neighboring countries closer to home such as Belgium, Denmark and Holland were plentifully represented at the show – not forgetting visitors from other well-established European markets such as France, Italy, Spain and the UK. There were also a good proportion of guests from the USA, the growth markets of the BRICS countries (Brazil, Russia, India, China, Southeast Asia) and even from more exotic locations such as Aruba, Mauritius or Greenland.

Picture courtesy of: HOMAG Group AG

Fig 1 (innovation at ligna)

Fig. 1: powerTouch – the new dimension in machine operation in the legendary InnovationCenter

Fig 2 (innovation at ligna)

Fig. 2: One of the biggest topics for the HOMAG Group: Batch size 1 production with individually networked high-tech machines for the entire process chain

Fig 3 (innovation at ligna)

Fig. 3: A lively buzz in HOMAG City

Fig 4 (nnovation at ligna)

Fig. 4: International trade fair: Around 56 % of visitors to HOMAG City made the journey from outside of Germany

Fig 5 (innovation at ligna)

Fig. 5: A group of visitors from Gabon arrives having made the long journey to HOMAG City


Shop Performance: Maximizing your Edgebanding Performance

May 16, 2013

Head Shot

With the introduction of particle and fiberboard as core materials in the furniture industry, which replace the more expensive solid wood panels, it became necessary to cover the visible edges of the furniture components. The question was how.

Panel edges are covered for cosmetic reasons, but also to protect them from accidental damage and moisture penetration. The unprotected edge of a particle/fiber board panel can be easily chipped at the top and bottom edges, especially with melamine laminates, and moisture can penetrate into the panel, which will swell the board and destroy its cohesion.

In addition to these practical reasons, a well-applied edge looks much better and provides infinite possibilities for product customization. The panel edges are small compared to the overall size of a piece of furniture, but by adding a different colour, a softer edge profile or even unusual dimensions, these edges can often define the look and overall craftsmanship.

The manual application of an edge requires skill, proficiency and time. To make this process easier and faster, most woodworking shops use an edgebanding machine. The variety of edgebanders on the market is enormous, and prices range from less than $10,000 to more than $1 million.

How do you find the right machine?

Some criteria will be determined by your production requirements, such as maximum required edge or panel thickness, the type of glue required for your materials, and the processing steps to get to the final shape of your edge. Each of these can be discussed in detail, but I want to focus on two aspects today: the speed of edgebanders and automation.

Automation

I often hear: “I don’t need automation, because I will only use the edgebander for a few hours a day.” At first glance this seems like a valid statement, but the time you are not spending with your edgebander is valuable time that allows you to complete other production processes (or just enjoy life). I will give you an example to demonstrate the value of automation.

Imagine you want to apply thin tape to all four sides of a cabinet front. After the two long edges of the front have been processed, the end trim saws need to be adjusted for the short edges. If the panels are not completely square and the end trim saws are left to trim exactly flush, they will mark the already applied edge tape on the long sides. Even a slight thickness variation of the edge tape can result in such damage. To avoid this, most end trim saws are swiveled from 0° flush trim, to trimming at an angle of 15° – 25° to give the saw blade clearance to the tape on the long side. The end trim saws are located under the safety hood, which is locked when the machine is operating, which is mandatory under Canadian safety regulations. You have to turn the control voltage off and wait for the safety interlock to release the hood. This will take about 10 seconds to allow the saws and cutters to come to a complete stop.

Then you open the hood, loosen each end trim unit and swivel and retighten each in the new position. This takes another 15 seconds. Closing the hood, restarting the machine and getting ready to feed the next part will require another five seconds. You may think 30 seconds isn’t bad and you don’t need to automate this process, but even if you only do this 10 times per day, it will cost you five minutes to angle the end trim saws and five minutes to swivel them back to flush trimming. That adds up to 10 minutes per day or 2,400 minutes per year (240 days/year). In other words, even a quick adjustment of a few seconds adds up to an astonishing 40 hours, or one week per year.

In this example you will spend one week of your valuable time swiveling the end trim units. A simple pneumatic cylinder can do this job in a few seconds, activated by a button on the machine controller. Now add the times necessary to adjust a top and bottom trimming unit, a scraping unit or any other post-processing unit your edgebander might be equipped with, and you realize how quickly these times add up. How long will it take to change a top and bottom trimming unit from 0.5 mm thin tape to 3 mm PVC edges or even thicker solid wood edges? On many edgebanders these changes require adjustments to two or even three settings per motor. An experienced operator may not need to run test parts after an adjustment, but most will do it anyway to confirm a quality setup. The whole process will take about five minutes for a single changeover. Calculate how many times you will change from thin tape to PVC (or from thin tape to veneer or solid wood) and back and than multiply this number by five minutes.

If the number you come up with takes your breath away, you need automation for your edgebander. In addition to the time you’ll save, you will also bring consistency to your production, even if you have different operators run the machine.

In general you can say that if your products are diverse or you produce in smaller batches, you will require more setups and will profit from automation on your edgebander.

Speed of the machine

It is a common misconception that faster edgebander have a higher productivity. This is only partly correct. Many factors influence the output of an edgebander. The best way to measure the productivity of an edgebander (or any other machine) is the number of parts that can be processed in a given amount of time. The speed of a machine will obviously influence productivity, but there are also other important criteria such as minimum work piece gap, change over times (see Automation above) or infeed control.

The following calculation will illustrate this. You have to edgeband 1,000 shelves, each 500 mm long, and you have to apply thin tape to the front. Edgebander ‘A’ runs with 14 m/min and requires a minimum gap of 900 mm between two work pieces (this time is necessary to bring the end trim units back into the starting position for the next work piece). Every 1,400 mm (500 mm part length plus 900 mm gap) you can feed a new panel into machine ‘A’. You will process 10 panels per minute (14 m/min speed divided by 1.4 m) and will need 100 minutes for the complete job. Edgebander ‘B’ runs only 12 m/min, but needs only a 500 mm gap between parts. Every 1000 mm (500 mm + 500 mm) a panel is accepted, which brings the production to 12 pieces per minute. Machine ‘B’ will do the job in 83 minutes. As you can see from the above example the spacing between the parts has a big impact on the productivity of your edgebander. But how do you make sure you get that spacing just right? If parts are spaced too far apart, productivity is lost. If they are too close together, then the machine goes into an emergency stop, the parts have to be removed manually from the machine and the memory cleared by running the machine empty. Again this is a lot of wasted productivity.

The best way to address this is by opening and closing the infeed of the edgebander, so that the operator cannot physically feed a part into the machine before it is ready to accept it. This feature will keep your parts perfectly spaced and therefore your productivity at the highest possible level.


PRESS RELEASE: HOLZMA Highlights at LIGNA 2013

May 14, 2013

Flexibility in Cutting Operations

HOLZMA_Bild_Picture_3_DustEx

Solutions to make daily work easier, to improve efficiency, to minimize errors, to increase flexibility and output – HOLZMA showcased a raft of innovations on this theme at LIGNA 2013. New technologies, new processes and a completely revamped product portfolio provide greater efficiency in panel cutting.

“To stay competitive, customers from trade and industry are being obliged to cut their production costs without sacrificing quality. All our LIGNA innovations will help our customers come even closer to achieving this goal,” comments Martin Kress, HOLZMA Product Manager. The interest they aroused among visitors to the fair was correspondingly high: “The amount of positive feedback we received and the many discussions we had with customers show that we are right on target with our innovations,” concludes Holger Bomm, Managing Director of HOLZMA Plattenaufteiltechnik GmbH.

To read the full article, please click here: HOLZMA HIGHLIGHTS LIGNA 2013


HOMAG Group on YouTube

May 13, 2013

YouTube

Subscribe to HOMAG Group’s YouTube Channel and get up to date information on all companies in the HOMAG Family.

Now Playing: Highlights from LIGNA 2013 and HOMAG City!

 

 

 


Shop Performance: Maximizing your Nesting Performance

May 10, 2013

Head Shot

Blue Nesting

Nesting is not a new technology and the woodworking industry is not the only industry using it. Originally invented in the leather industry to optimize the yield from each piece of leather, the nesting process became very popular in the woodworking industry in the early 1980s. The nesting process provides unique advantages, which make the technology well suited to small start-ups as well as established mid-size production shops.

Because of its popularity there are many suppliers offering a wide range of solutions, which can be confusing not only to the first-time buyer, but also to experienced professionals. Here are some of the many criteria that determine what might be the right machine for your application?

  • What capacity do I require?
  • Do I need a drill block?
  • What is the right table size?
  • How many tools do I need?
  • What kind of software do I need?
  • How much vacuum do I need?

All of these questions are important and need to be answered prior to a purchase decision to avoid surprises later.

In this article I would like to focus on only one of these questions – What is the production capacity of the machine? How many sheets will be cut at the end of the day or shift? To answer this question we have to recap the process

of nesting.

  1. Prepare and position a new panel on the spoil board.
  2. Select and start the program.
  3. Run the program with all drilling, grooving and routing operations.
  4. Clean the nested panel.
  5. Remove, sort, check, label and stack the cut parts.
  6. Clean the spoil board

This sequence of steps has to be repeated for every sheet that has to be nested. In addition tools and spoil boards have to be re-surfaced or replaced in intervals that depend on the materials and patterns cut.

The necessNestingary time for each step depends on many factors, for example:

Process step 1

The placing of a panel depends on the size and weight of the panel and whether the panel can be placed manually or if a hoisting device like a vacuum lifter is required. Are the panels stored beside the machine or do they have to be located in the warehouse and transported to the machine every time?

Process Step 3

The time required for the machining process depends on the size of the nest and whether special profile tools are used e.g. for the manufacturing of doors. Is the nest cut in one or two steps to reduce the cutting pressure and optimize the hold-down of smaller parts? How many holes have to be drilled? What is the speed of the machine or what type of tool is being used for what type of material? For the production of case goods even the construction method of the cabinet will have an influence on the processing time. To cut the nest for a cabinet using blind dado will take more time than a cabinet that will be doweled.

Process step 5

Again the size of the panel has a significant impact on the time necessary to unload the machine bed. The number of parts, the time spent on inspection and the complexity of sorting/ stacking the finished components are all factors that make this process step very time consuming. The application of labels to identify parts will extend this time even further.

Looking at the three process steps I described above, it becomes apparent that the biggest opportunity for capacity improvement lies in the last process step. After the machining of the panel is completed, the cut parts have to be manually removed from the machine table. The machine (your investment) cannot produce until the operator has completed that task. With the addition of an automatic push-off device the complete panel (all parts Maximizing your Nesting Performance still surrounded by the skeleton/ frame) will be pushed off the machine table onto an outfeed conveyor. The machine table is quickly cleared, the next panel loaded immediately and the program started. This way the operator can remove, sort, check and optionally label the cut parts from the outfeed conveyor while the machine is already processing the next panel. With the right pusher system the spoil board can also be cleaned (step 6) while the complete nest is pushed off the machine table.

The following calculation is based on what I see happen in shops every day. The times are averages and they will illustrate the influence of an automatic push out device. Let us assume we process kitchen cabinets out of 4′ x 8′ melamine chip board.

To place the board onto the machine and to load the program takes approx. 30 seconds. To run the machining program will require about four (4) minutes, while the offloading of the parts and removal of the waste pieces will take another three (3) minutes. With 30 seconds to clean the spoil board the total cycle takes eight (8) minutes for a completely manual operation.

By using a system with automated push out device, the loading of the board and the program selection will still take about 30 seconds, and the machining will also still require the same four (4) minutes. But instead of the time consuming off-loading of the single parts and waste pieces, the whole nest will be pushed off the machine and the spoil board cleaned in 30 seconds. The entire cycle takes only about five (5) minutes.

Let us look at what effect this has on the numbers of sheets produced during the day. The manual nesting cycle takes eight (8) minutes, which translates into 7.5 sheets per hour or 60 sheets per day (assuming 8 hours per day). Now we have to consider down time for replacement of tooling, re-surfacing and changing of the spoil board and some preventative machine maintenance as well as breaks for the operator. From experience we say that a machine in this environment will be available for production about 85 per cent of the time. Fifteen per cent is spent on the maintenance items listed above. This reduces the daily production total from 60 sheets per day to 51 sheets per day.

With an automatic push-off and cleaning system, where the overall cycle time is reduced to five (5) minutes, the output can be increased by 31 sheets per day, an astounding 60 per cent performance gain.

By moving the processed parts as quickly as possible from the machining to a holding table, the nesting router can be back in production 60 per cent faster. There are also automated feeding systems to load new sheets onto the machine table, but the time difference between automatic and manual loading is insignificant and the output of the nesting machine is not affected.

For cabinet shops that have a demand of 30 sheets or less per day a stand alone nesting machine will easily meet the current demand as well as allow sufficient room for future growth. Companies that have a demand of 50 sheets or more will need to consider a nesting system with push-off capabilities.


Follow

Get every new post delivered to your Inbox.

Join 319 other followers

%d bloggers like this: