Precision Aerospace Machining and the Seven Wastes of Lean Manufacturing (pt1)

As I talked about in the last post, I will be examining the seven wastes identified in lean manufacturing and showing how CNC Industries handles each in a high  mix / low volume aerospace machining environment.  The first of the seven wastes is Overproduction.  Overproduction is using more resources than necessary to create and deliver a part to the customer.  Overproduction can be further defined as producing more, sooner or faster than what is necessary.  Elimination of overproduction is a large factor in Just-In-Time systems that many manufacturers are focusing on.  Just-in-time has a goal of eliminating inventory and producing or ordering material to arrive just in time for the operation that it is needed in.

Batch size is a large factor to consider when looking at overproduction.  It is important to not produce too many parts – this leads to storing the excess parts in inventory for an excessive amount of time.  However, in an aerospace machining environment the complexity of the parts is prohibitive to a true just-in-time system.  When a part may take 6-8 weeks to manufacture and only a small amount of the parts are needed each week to create a new batch for every shipment would necessitate setting up a new batch each week and having multiple batches open at the same time.  The logistics of tracking all of these batches combined with the costs and time of setting up a machine each week for the same part would be prohibitive.  In addition to the setups and the logistics, material orders would necessarily be smaller and more frequent which would eliminate cost savings in ordering and require more time in purchasing and receiving material.    Of course a production facility can avoid many of these pitfalls by having specially made machines that are dedicated to a certain process or part.  In a high mix environment, machines tend to be needed for many different parts and cannot be dedicated to a select group of part.

Instead for a high-mix low volume aerospace machining facility, selecting the right batch size includes factoring in the setup costs and the lead time to create a batch that is a reasonable multiple of an individual shipment.  In the above example it may be seen that a batch that is the equivalent of 10 weeks of shipments is the optimum size to reduce overproduction and minimize inventory storage time as well.  The key is to account for holding costs, batch setup costs, and the estimated demand on a given machined part.  Our ERP system, Job Manager 2, has a module to handle these calculations and give a suggested batch size in order to lower the overproduction to the lowest feasible amount.  Selecting the right batch size is of paramount importance in attempting a lean operation in an aerospace machining environment that tends to have high mix and low volume production.

CNC Industries solves the problem of overproduction waste through efficient information handling and analysis.  We have strong visualizations of our production and inventory and we regularly examine our production to ensure optimum batch size.  Our ERP system both handles the batch size determination and the scheduling of the new batches to ensure that parts are produced at the right time and with the right quantity.  When maintaining a Kan-Ban System for our aerospace customers it is vital that we both maintain enough inventory to handle their surges in demand, as well as minimize our batch size to allow us to produce the wide variety of parts that are requested.

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CNC Industries is a Fort Wayne, Indiana based machine shop specializing in precision CNC machining, fabrication and assembly of application-critical and custom machined parts for the Aerospace, Defense, Medical, Industrial and Transportation  markets.   The company presently employs approximately 55 people.

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May 7th, 2010|Tags: , , , |

Lean manufacturing and Aerospace Machining, Low Volume / High Mix production

Lean manufacturing is a concept that most businesses strive for and many claim.  The primary concept of lean manufacturing is eliminating all unnecessary costs and time associated with production.  The primary way most companies will start with Lean is to manufacture parts as fast as possible – to get as much production from each machine as possible.  As the cycle time decreases wasted machine time decreases as well.  This is a great start to lean manufacturing, but it is also the most common method.  Many companies focus on cycle time reduction almost entirely in their lean efforts.

Cycle Time reduction works best in environments where a machine shop is producing the same part for a long duration.  This is typically a full production shop and will have dedicated machinery to optimize a single process to the fullest extent possible.  In the aerospace machining industry or custom machined parts production we are not producing high enough volumes of many parts to dedicate an entire machine to a single part.  As such aerospace machine shops and custom manufacturing shops (or job shops) will face additional difficulties in going ‘lean’.

Adjusting the cycle time down by 10% is not as effective of a lean tool when machine time may only be 60% or less of the time spent on producing a given part.  The lower the proportion of machine time to non-machine time in a job, the more important it is to go lean in additional ways.  in connection to that – the more often a machine needs to be set up for a new job the more non-machine cost is in the job – for reference a single aerospace machined part may have 5 or 6 separate  machining operations each requiring an additional setup on the machine.  Transferring the material to different areas, setting up the machine, inspecting the part throughout production, and other items add to the non-machine time at every step.

Over the next few posts I will be looking at the 7 wastes identified in a typical lean manufacturing implementation and how CNC Industries deals with each on in relation to our low volume / high mix work.  We have some production jobs as well, but those are handled in slightly different ways, and will be discussed at a later time.

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CNC Industries is a Fort Wayne, Indiana based machine shop specializing in precision CNC machining, fabrication and assembly of application-critical and custom machined parts for the Aerospace, Defense, Medical, Industrial and Transportation  markets.   The company presently employs approximately 55 people.

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May 5th, 2010|Tags: , , , |

Green & Energy Efficient CNC Machining

This is a guest post from Jack Lundee, thank you for your contribution!

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With heavy development of prototypes and the never slowing business to business construction/adaptation of plastic, metals and wood, laser sintering and stereolithography have become widely energy efficient. Yielding the same, if not better, output, these large machines have rapidly become greener.

Utilizing CNC (Computer Numeric Control) and CAD, prototypes are able to develop unique designs and shape various metallic, plastic, and wooden materials into appropriate form. Although, since the first CNC machines were built (1940), there have been significant strides in providing a more energy efficient machine. Ranging from $1,000 to nearly $50,000 and weighing in at close to 6000 lbs, these machines can eat up electricity much like a large industrial oven used in a pizza shop. Although, this is a tremendous improve from past machines, coming it at close to 50,000 watts. Newer machines can range anywhere between 800 and 6,000 watts, depending on the make and price. Again, this is still close to the electric drain of a hot tub or stove.
Despite, this is quite a significant difference – It’s easy to compare this to a domestic furnace, whereas older furnaces were built to last, newer ones are built to reduce electricity costs and promote sustainability. With more expensive machines running at close to 4000 RPMs, (revolutions per minute), it’s no wonder why they require so much juice. The engine/motor eats up the most power, along with the CPU and cooling system, which leads me to my next point.

The machines ability to reduce business expenses effectively compliments its technological advances. This includes things like a brushless motor. Prior to construction,
motors were subject to:

• Worn brush heads
• Sparking and electricity (noise)
• Limitation of speed (efficiency)
• Slow cooling

With the implementation of a BLM (Brushless Motor), these machines not only have greater capabilities, but provide low costs and greater efficiency.
As tool manufacturers are met with new market demands, they must also inherently adapt their business and machines. This is especially true for those in the niche of rapid prototyping. Adapting to new technology and market demands is essential for any business conducing sintering, cutting, welding, stereolithography and much more! With this, consumers should be green conscious, particularly in the development of CNC/CAD machines.

May 4th, 2010|Tags: , |

CNC Value Added Services for Aerospace Machining

Airplanes and other aerospace items need to be ordered well in advance of when they are needed.  With long lead times and relatively low volumes – a good jet sells 200-300 units in a year – aerospace companies can get a pretty good read on what their needs will be for the next year or so.  To aid our customers of aerospace machine parts we have added several services without increasing our costs to our customers.  You can read all about our aerospace services in detail at our aerospace machining page or our aerospace machining definition page.

Our advanced information management capabilities allow us to provide long term stocking arrangements or kanban shipping.  In many cases we hold the inventory for our aerospace customers and allow them to draw from our inventory rather than maintain their own inventory.  We use various just-in-time production techniques to keep up with our customers’ assembly demands.  For one of our customers we deliver parts on an demand-flow basis directly to the assembly line.. In addition we are able to build to an annual forecast, rather than directly to individual purchase orders. Machining the parts to an annual forecast, while we also maintain the inventory, combines to save our customers considerable cost and time.

CNC Industries has the ability to handle many different methods of receiving orders.  We have multiple electronic systems, such as Exostar which many aerospace companies use, through which we receive new orders. We also have many customers who send electronic triggers through email to indicate additional requirements.

Some other value added services are more transparent to our customers but are still important. Our standard practice of handling machined parts within our facility is to create unique totes and tubs to protect the parts throughout the entire manufacturing process.  We have strict maintenance policies and keep our facilities climate controlled, clean, and well lit.  One traditional view of machine shops is that they are dingy, dirty and dangerous to walk around in. When coming to CNC Industries, we expect that you will immediately notice the difference in the care we take in maintaining our facility. Visitors frequently tell us that our facility is the cleanest and most advanced manufacturing facility that they have seen.

April 30th, 2010|Tags: , , |

Changes to CNC Industries website

CNC Industries is going to be adding to our main website content.  In examining our website we feel that we are not addressing some topics enough on our main site.  While I am attempting to add content to our blog to help fill these voids, we are going to be adding many new pages over the next while to fill in the gaps that we see as present.

The first additions that we have made are aerospace machining and the definition of aerospace machining.  We are focused heavily on aerospace machining, and we want our website to reflect this.  The purpose of having two pages on essentially the same topic is to provide the detail information that not everyone will be familiar with.

While our website is very informative and serves to provide the same information that you will get from most shops, we are not satisfied with meeting the standards.  We want anyone that comes to our site to be able to tell right away if CNC Industries will be a good fit to be a supplier for them.  Our aerospace machining page is the first in a series of pages that is designed to address this issue.

Our Definitions area of the website will become filled with basic information about precision machining, and other topics which relate to CNC Industries.  We will look to explore what defines precision machining and differentiates it from standard machining.  We will of course look at what goes into aerospace machining, industrial machining, medical machining, automobile machining, and military machining and why CNC Industries has chosen the focuses that we have.

April 27th, 2010|Tags: , , , |

What is aerospace machining?

Aerospace machining is a subset of CNC machining.  Specifically aerospace machining (as you can tell from the name) deals with parts manufactured for use on airplanes, satellites, the space station, or other aircraft.  Aerospace machining is defined by its complexity, use of lightweight high strength materials, rigid requirements and specifications, and the strict precision necessary for the manufacture of the parts.

Components made by a cnc machine shop for use in the aerospace industry will typically be designed to be assembled with other components – whether machined or stocked parts.  As such, it is vitally important for a machine shop focused on aerospace machining to be able to produce high precision machined parts every time.

Parts may be made from a variety of different materials.  At CNC Industries, we have focused on aluminum which is a major component in many types of aircraft.  Aluminum machining has it’s own areas of complexity and is very different from steel machining that may be more familiar to automobile manufacturers.  Aluminum is a focused material in aerospace machining because it is lightweight yet still very strong.  Titanium is also used for many space oriented components, but due to the cost and increased difficulty of machining, is not as prevalent in traditional aircraft.

April 19th, 2010|Tags: , , |

Importance of proper quality control in precision machining

Poka-yoke, fail-safeing, mistake-proofing, any way that you call it, quality control is critical to running a precision machine shop.  Quality control comes in many different flavors.  All machine shops will have an inspection or metrology department to check for quality before any parts leave the facility.  It is often less expensive and more efficient to create quality at the source.

At CNC Industries, we focus on creating advanced fixtures to prevent many of the common problems that might occur in the machining process.  Our Pre-Flight meetings are an opportunity to talk through any and all issues that might affect a new custom machined part.   This process is critical when running difficult aerospace precision machined parts or military parts.  With the complexities of the aerospace components that we make, it is vital that all potential pitfalls in production are identified early in the process.  It is at this time we are also determining the type and design of the fixture that we will use to prevent problems in production.

No matter how good the fixtures and the production router are, there is still a chance of problems occurring throughout the process.  At CNC Industries, we have well trained personnel on all machines that are capable of running their own in-process inspections to detect any problems throughout the manufacturing process.  All of our parts are assigned frequent in-process inspections to ensure that no problems creep in undetected.

With several of our aerospace customers performing no incoming inspection it is critical to have adequate inspection processes throughout our production.  Our final inspection process is thorough and performed on best-in-class equipment to provide our customers with the utmost confidence that they are receiving quality parts with each delivery.   At CNC Industries we take full accountability for all of our parts – from the initial purchase order to the final delivery of the machined parts to the customer.

April 16th, 2010|Tags: , , , |

Ordering custom machined parts with a new machine shop supplier

In continuing the last post on finding a new precision machine shop for custom machined parts, I am going to go over a bit of what to expect with the first order or two.

Communication is still the key to the process.  At CNC Industries, we have often been told that our communication is a large part of the reason that we are among their favored suppliers.  Precision Machining is a relatively tricky process still today.  The information overload that comes with each part drawing can often lead to overlooked features or specifications.  Aerospace components often contain numerous mil-specs, large amounts of technical call-outs, and even purchase order specifications.  Even parts that are less complex than aerospace components may have critical details that are easy to overlook.  Part Revisioning can cause increased complexity and another chance to overlook some crucial piece of information.  If you have not checked yet, it is important to check into your supplier’s information management system.

It is important for the machine shop that you are starting out with to ask any clarifying questions necessary to get the complete picture of the machined part that they are producing.  Ideally all questions from the machine shop should have come out during the RFQ process.  However, it is not uncommon for the engineering team to take a deeper look at the part as they prepare the production router and fixture.  In the RFQ process of a new customer that we acquired we were able to ascertain that they had mislabeled a set of drawings that they had sent out for us to quote.  Through our examination of the part we noticed that some of the details seemed to be wrong for the stated use of the part.  We consider our discovery of this error on their drawing to be a large part of the reason that we received the initial purchase order.

Another important aspect of the first job is to carefully select what part or parts you will be sending to the new supplier.  It has worked best at CNC Industries to have a new customer order a variety of potential parts in the initial order.  It is good to have a scope of potential work complexities.  If you are to start doing work with a new precision machine shop and only send small simple work to them, you may find that they are not capable of handling the complex machined parts that you want to order down the road.  Likewise if you are sending only complex parts and you want to have a single source to deal with for machined parts, you may find that the machine shop is not price competitive on  simpler parts.  One way to deal with both of these issues is to give at least a relative expectation of cost to your new supplier, ie: ‘for our simple parts we typically pay half of what we pay for the complex parts’.  As you can see from our parts profile page, CNC Industries works with a large variety of complexities and quantities on a daily basis.

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CNC Industries is a Fort Wayne, Indiana based machine shop specializing in precision CNC machining, fabrication and assembly of application-critical and custom machined parts for the Aerospace, Defense, Medical, Industrial and Transportation  markets.   The company presently employs approximately 55 people.

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April 14th, 2010|Tags: , , , , , |

Needed: Precision Machine Shop for Custom Machined Parts

Many companies that need custom machined parts are not sure of the process of getting started with a machine shop supplier.  In this post I will go over the basic process.  As I talked about in a prior post about evaluating a precision machine shop, it is important be careful in selecting a supplier of custom made parts.  In society today it is normal to simply  go with the lowest price on pretty much any purchase.  With the modernization of production, it is normally safe to assume that any product purchased will pretty much be the exact same no matter where it is purchased.  With custom machine parts, it is important to ensure that the supplier is qualified and capable of making the part.

Large companies will spend a large amount of time vetting a new supplier that makes custom machined parts.  Two recent companies that have started with CNC Industries, spent an average of 6 months in the process of examining our company before sending their first production purchase orders to us.  In the process of examining our company the new customers looked at our production capabilities, our information management systems, our  inspection processes, and the custom machined parts that we have made in the past.

Now a small company will probably not have a team that is used to handling this process.  Many small companies may never have had to order custom parts before.  For those companies 6 months research of a new machine shop supplier is probably not an option that they can consider.  In that case, an examination of the website of the potential supplier is worthwhile of course, but anyone can have a nice web presence.  It is still possible to feel out a new machine shop without the lengthy process that large companies go through.

One way to start is to simply send out a Request For Quote  (RFQ) to the machine shop in question.  I would certainly recommend not simply going off of the price of the quote as the only determinate of which company to go with.  After receiving the quotes, you will probably see a wide variety of prices come in.  After getting these quotes call up a couple of machine shops from different price levels and ask to talk about how they are going to manufacture your part.  You will be able to  get a feel of the company by how they describe the process.  Some questions to ask them:

  • How did the come up with the price that they did?
  • What engineering steps take place before manufacturing?
  • What process control methods do they employ to ensure quality throughout manufacturing?
  • How is their inspection done?
  • Are they certified ISO or any other appropriate certification?

and one other that has been useful to many of our customers:

  • Are there any changes to the part that the machine shop would recommend in order to lower production cost?

We have been able to save many of our customers considerable amount on their prices by making minor non-functional changes to the part to enable easier machining.  Engineers that are focusing on assembly and pure functionality of the parts that they are designing may add features into a part that slow production time considerably but are not necessary to the functioning of the component (undercuts, overly tight tolerances, odd size material requirements, unusual material types etc)

Of course ask any other questions that you see appropriate.  It is important that you feel comfortable working with the machine shop that you decide upon. Our philosophy is that the most important measure of a machine shop is that of customer satisfaction.  We believe in what we call the 3 legged stool: Price, Quality and Customer Service.  Each of these attributes contributes to the overall value of the precision machine shop.

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CNC Industries is a Fort Wayne, Indiana based machine shop specializing in precision CNC machining, fabrication and assembly of application-critical and custom machined parts for the Aerospace, Defense, Medical, Industrial and Transportation  markets.   The company presently employs approximately 55 people.

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April 9th, 2010|Tags: , |

Addressing Precision Aerospace Machining Difficulties

In the last post I talked about the difficulties of precision machining aerospace parts.  I would like to address these issues and specifically talk about how CNC Industries handles each of them.

The first issue, namely tight tolerances, is addressed in a few different ways.  The first step is to make sure that the equipment being used is capable of the types and quality of machining necessary.  Proper maintenance is also an important step, many companies lay-off their maintenance staff at the first sign of a downturn.  Maintenance is a key aspect of CNC Industries’ strategy.  The second step of ensuring that tolerances are met happens in engineering.  Engineering staff creates fixtures, work drawings, and machine code to run the part correctly.  Engineering is another key area that CNC Industries believes should not be cut too early.  The third step is to ensure that information about the part flows correctly.  To aid in this we have written our own ERP system.  Job Manager 2 is a real time system that enables information to be updated and transferred throughout the facility so that any changes made are implemented immediately.

The second issue, the amount of material removed, is a prime engineering problem.  The fixture created for each part must take into account the changes in strength that the material will go through during the machining process.  With fixturing being such an important aspect of creating a good custom machined part, we go through a process we call the Pre-Flight Meeting.  In this meeting our top management, quality assurance, engineers, and shop floor supervisors meet to discuss any issues that we see as important to the manufacturing of the part.

The third issue, external quality standards, is again addressed through information management.  Our ERP system allows each part to have an unlimited amount of quality standards.  The part routers created in Job Manager 2 allow for any and all detailed information to be added to an individual operation.  The amount of detail contained in each router, in addition to the real-time ERP system allows us to ensure that all of the information needed to complete a job to the full satisfaction of our customer is accessible at all times.

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CNC Industries is a Fort Wayne, Indiana based machine shop specializing in precision CNC machining, fabrication and assembly of application-critical and custom machined parts for the Aerospace, Defense, Medical, Industrial and Transportation  markets.   The company presently employs approximately 55 people.

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April 5th, 2010|Tags: , , , |
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