Does Mixing Shop Orders Make You Nervous?

Not Dynamic Nesting of Mixed Orders

Not Dynamic Nesting of Mixed Orders

Does the thought of mixing orders in a nest strike fear into your heart?  Or does it just feel better to keep your items separate, like food on a tray -  no mixing allowed.

This probably isn’t you, but maybe you’ve heard of others, who under penalty of death, will not mix orders when nesting.  It’s true.  We hear about it a lot.

Although I’m having a little fun with it here, some have very real concerns about mixing parts from different orders, jobs, customers on a single or series of nests.  And those concerns are probably based in real-world, nightmarish experiences.

Today, we’ll look at the challenges of mixing orders and some best practices and tools to address them.  Then we’ll consider why mixing orders would be beneficial when done right and with the right tools.  Finally, we’ll ask the questions you may be asking to determine if mixing sheet metal nesting orders is right for you.

Challenges in Mixing Orders When Nesting

Shop Floor Chaos

The biggest concern we hear about mixing orders, jobs, customers or any other non-like entity in a nest is that it will – and does – wreak havoc on the shop floor.  The machine operators are moving as fast as they can to keep the line going smoothly.  When the orders are mixed coming off the nest, it simply adds complexity to their work to have to sort the parts by order, job, or customer and keep everything moving smoothly.  And then there is the challenge of where to stack everything, once it is coming off the cutting bed.

Best Practice to Address Shop Floor Order Management Chaos

 The shop floor chaos of managing orders resolves into two issues.  The first is process-management.  With the part, order identification system and the right visuals – plots and / or labels, and the right reports – the machine operator can easily identify the parts and orders.  When the process is made doable, the task is manageable and shouldn’t add to the job complexity.  It should simplify it.

 The other issue is a culture or mindset.  If anyone, including myself, perceives that a job will be made harder and there is nothing in it for me, there will be pushback. I understand.  That makes sense.  The tool to leverage here is a clear understanding of the process, everyone’s role in the process, and how the change will benefit everyone including the operator.

 Job Costing

Another concern we hear about mixing orders is job costing.  If the sheet isn’t dedicated to an order, job, or customer how can the parts (machine time and material) be costed accurately?  Or what if the customer supplied the material, then the job can’t be mixed with anything else, because it is dedicated, customer-specific material.

Best Practice for Job Costing

The technology exists today to cost a job (machine time and material) by sheet and / or by part with the right nesting software.  So, even if orders are mixed, the individual piece-parts can be costed separately and tied to their respective orders, jobs or customers.  There is no reason to separate orders simply to be able to cost a job accurately.

Order Triage

Finally, if you are mixing orders, some say, there is no way to set priorities based on job, part, customer, order, etc..  I must put the orders through as whole orders in the order in which they are needed.  How can you juggle orders, material and priorities and keep everything moving smoothly?

Best Practice for Handling Order Triage

Prioritizing jobs, parts, orders by their due date or an arbitrary status is easily done in conjunction with an ERP/MRP system or through manual assignment in an advanced sheet metal software product.  The software can order the parts with the priorities or due dates you assign, and respect your need to obtain a satisfactory material efficiency.

Mixing Orders | What’s the Benefit?

What would be the upside of mixing orders?  Why would any manufacturer ever do such a thing?  Would it be worth the effort?

Material Efficiency

One possible advantage for you of co-mingling orders (jobs, customers) would be an increased material efficiency.  If there are more parts from multiple orders in the order bucket, then the sheet metal nesting software has more part options to work with when creating a nest.  More part options naturally – assuming a variety of parts reflecting different sizes and shapes – would lead to increased material yield.  For example, if the nesting software can look at 250 parts from five orders all with near-term due dates, it can choose from several options for each nest, and ultimately choose the best – again recognizing a number of priorities – due dates, material efficiency, and throughput.  It’s not always the case, but in this situation “more” parts is “better.”

Sheet Utilization

Manufacturers typically have some materials that get heavy use, and others that get light use.  You may run 18-gauge aluminum all day long and only on occasion run stainless steel.  If you were to mix the stainless steel orders from multiple jobs or customers, then the chance of a remnant or irregular sheet metal remnant would be minimized.  Alternatively, with a greater density of parts from combined orders, the manufacturer could do some sheet size estimating or forecasting.  With a clear window on future needs he can standardize the sheets, order in more favorable quantities, or move to a JIT sheet ordering system. 

Grouping Like-Downstream Process Parts

In most operations there is at least one downstream operation performed on a part after nesting & cutting.  Whether it’s welding, painting, forming, assembly, or something else, there is a scheduling challenge to be managed.  Some processes take longer than others, and ultimately all the parts for one assembly should come together at the same time.

By mixing parts from various orders but segregated by their downstream process, i.e. welding, the parts can be scheduled to give the downstream process plenty of time and still come together for assembly or shipping at the same time.  Welded parts could be cut with a 2-day lead time, where painted parts may only need 1-day before assembly.  Using this thought-process, the set up and tear down time for the downstream processes can be minimized because more like-parts are coming through at one time.

Filler Parts

If the engineer is mixing orders, then he has the opportunity to introduce “filler parts.”       Filler parts can be “second class” parts that only are created in the sheet voids in and among the priority parts.  They would, by definition, be a different order.  This “second class” order may possibly have a later due date, a different first-choice material type, or may be made for inventory.  Regardless, its urgency is less than the priority parts, and is treated as a subordinate order – a mixed in order.  By using filler parts the engineer can increase material efficiency by making them out of material that would otherwise be scrap with nominal programming time.

Evaluating Order Nesting Options

So, we’ve assessed mixing parts and seen where there are indeed pros & cons to the strategy; challenges and best practices. This leaves us with a couple questions.

Do the pros outweigh the cons enough to consider this option?  Ask yourself, what could be the gain in material efficiency?  Is there a compelling argument? Could we reduce shop floor chaos by better timing the orders that go downstream?  Is there an opportunity for filler parts to be introduced?  Would filler parts save us time and material, if so, how much?

In Summary

Each manufacturer has to assess independently whether mixing orders is a viable option.  With good information at hand, access to nesting software able to meet the challenge, and an upfront discussion with the stakeholders involved in the process, a clear choice can be made.

How about you?

How do you handle a variety of orders?  Do you have a solution to some of the challenges presented here?  Maybe a best practice to offer.  Share your ideas.

For more information on sheet metal software capable of handling mixed orders in a dynamic nesting environment contact Optimation.

Notice: This work is licensed under a BY-NC-SA. Permalink: Does Mixing Shop Orders Make You Nervous?

3 comments on “Does Mixing Shop Orders Make You Nervous?

  1. Pingback: How well is your part ordering system working? | Optimation Nesting Software Blog

  2. Pingback: 4 Ways to Maximize Material Yield on Sheet Metal Remnants | Optimation Nesting Software Blog

  3. Pingback: JIT Nesting Software Helps You Respond to Changes in One Machine Cycle | Optimation Nesting Software Blog

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