Make the Most from Remnants

Advanced nesting software plus a well-managed plan turn remnants into profits

Advanced nesting software

Once a nest is completed, a crop can be made in a straight line or following the contour of the parts to separate excess material. Image courtesy of Lantek.

In an ideal production world, every sheet or plate of material would be a one-and-done—loaded, nested, and cut, leaving a thinly held together skeleton to be recycled. But the reality is that large or odd-shaped parts, a focus on just-in-time production rather than cutting extra parts to be stocked, and increasing material costs contribute to left-over material—remnants that carry too much value to economically scrap.

Dealing with remnants carries its own costs and can be awkward. Their irregular shapes can consume considerable amounts of floor or rack space. Working capital is tied up in material that might not be top of mind when planning a job. The investment accumulates right along with the unused stock.

A stringent management plan and advanced nesting software can shift stacks of remnants from the cost side of the ledger to the profit side.

“Today it is more and more commonplace for nesting software to manage material inventory, either directly or indirectly,” said Derek Weston, CAM software product marketing manager for Hypertherm. “If the plate is not consumed, typically the last cut is to separate the skeleton from what remains as usable plate. The remnant is then attributed back into inventory with its own electronic record for nesting as part of another job.

“Inventory can be maintained by the nesting software or possibly through integration with a third-party MRP/ERP software for centralized inventory. The intent is that users have visibility and easy access to partial plates, remnants of various sizes and thicknesses, as well as full plates.”

If remnants are saved in a geometry file that the MRP software can read and display, the sales team may also be able to view a complete picture of material availability and take it into consideration when quoting a job.

Managing a System

Remnants on the shop floor must exactly match the information in the database for a remnant management system to be successful. Any deviation in data can add time to a job,perhaps requiring an operator to search for a remnant or measure the material because electronic records are incomplete or inaccurate.

Pierre Slabber, owner of Sectura-SOFT, said, “It is difficult to keep the virtual and reality in sync. You have to have a well-documented remnant management plan in place that can be enforced by management and followed by programmers and machine operators. Everyone needs to understand the importance of the program.

“Marking and storing remnants are an important part of the plan. If the nesting system has the capability to etch the name on the remnant, then it should be marked before it leaves the machine. Preferably store the remnants in a rack system rather than in piles to allow operators to retrieve the remnant without moving other material. This will also save time for programmers so they don’t need to check if a remnant is on the top of a pile before they designate its use.”

That means that every remnant is identified and used only as directed. A remnant of similar size and shape cannot be substituted for a job just because it is more accessible than another. Weston agreed. “It takes only one person to not follow the process and grab the first remnant that fits the job, and the entire system begins to break down.”

Sectura SOFT nesting software screenshot

Exact dimensions of an irregular remnant need to be saved in a geometry file that MRP software can read and display. Image courtesy of SecturaSOFT.

A well-managed remnant system can fine-tune production procedures. For example, if an error results in a scrapped part, the material used for that part and its replacement must be accounted for in the database.

“The most important problem to address in a remnant management plan is how to handle scrap parts. This is the single biggest problem I’ve seen,” said Slabber. “If an operator scraps a part and cuts another out of a remnant, that remnant and the database are not in sync. When this happens, the programmers have to run out to the shop and measure a remnant before they can schedule its use. To save their own time, the programmers are going to schedule full sheets. There has to be a safe environment for reporting scrapped parts that can be processed with the next program or they have to be able to update the remnant on the reports sent back to the programmers.”

Defining Remnant

“Part of the plan should be the criteria for the programmer to create a remnant. Give the programmers clear criteria, easy guidelines for a go/nogo decision. You can base guidelines on weight or cost. It’s not going to be exact, but you can calculate the cost to store and reuse the remnant. If it costs more to store than reuse it, sell it for scrap,” Slabber said.

Material handling costs are an integral part of the evaluation. Loading and unloading a remnant costs the same as handling a full sheet or plate. The same setup time gives you less cutting time. Still, efficient, knowledgeable, and flexible management of remnants can increase material yield and add to the bottom line.

One creative possibility is using one load/unload for two jobs. Immediately after a nest has been completed and a remnant generated, schedule that remnant for another job. Additional handling and storage will be eliminated.

Asier Ortiz, chief technology officer at Lantek, said, “Several factors impact when to reuse or scrap material, including the type of material, the size of remnant generated, the possibility for reuse, the characteristics of the machine, as well as the cost of storage. Expensive materials are more likely to be reused.

“The software has to have a powerful capability to allow handling the remnants according to the company’s desires. Also, there needs to be the flexibility. A programmer needs to be able to make a decision in real time on a nest within predefined rules.”

Getting the Most Parts

Once the remnant management system is established, identifying and nesting on remnants can increase material utilization and save a company money.

A part list can be manually selected within the nesting software or a bill of materials may be imported. The software is then often directed to nest the parts in the most efficient manner possible on any available inventory.

Combining parts from various customers with the added ability to filter by a number of variables such as due date, customer name, and material requirements can give the nesting program a larger mix of part sizes, quantities, and geometries to work with. This in turn gives it more options to create an efficient nest.

Remnant software performs trials on materials

Advanced remnant software performs trials on available materials to find the most efficient material use before committing parts to a nest. Image courtesy of Hypertherm.

“The software will perform nesting trials, actually nesting on each of the available full sheets and remnants before committing the parts to a nest. It cycles, using various algorithms to fit the parts most efficiently to provide the best material utilization for that subset of parts,” explained Weston. “The software module provides visibility and makes it easy to pick the most suitable material for a job without compromising the overall cycle time.”

The program can be directed to prioritize nesting parts on the remnant inventory before using full sheets, increasing the overall turnover and clearing space dedicated to inventory storage. Alternately, the software can be directed to nest parts on a combination of partial and full-size material to achieve the most efficient production plan.

Choosing Straight or Profiled Edges

The shape of a remnant can vary—to a point.

“Usually programmers automatically crop remnants from the original material, having set up crop parameters within the software preferences,” Weston said. “Once a nest has been completed and there is excess material, a crop is made in a straight line or roughly following the parts that were cut from the nest. The downside to a nonlinear cut is that you could end up with fingers of material sticking out, which is not ideal from a safety standpoint or for optimal racking, especially for thinner materials. So there is a compromise between not wasting too much material and creating a remnant that is dangerous and difficult to handle.”

Large circular remnants can be included in the remnant inventory. Some advanced nesting software has the ability to take the material from a part’s large internal diameter and put it back in inventory rather than nesting other parts within it.

Remnant Software and Attitudes

“Managing a remnant system and using electronic inventory is an organization shift, a change in work flow, processes, and procedures. It takes buy-in and commitment from the nesting operator, the production manager, the machine operators— any individuals associated with handling the material from storage to machine,” said Weston.

“We are also seeing a growing number of companies integrating nesting software with their MRP/ ERP systems. This approach often provides more parts to work with and real-time job updates. It is another tool to optimize material and reduce double data entry, which makes companies more productive and helps minimize potential errors. It can have a very positive impact on customer responsiveness via reduced delivery times,” Weston continued. “With advanced software capabilities, material optimization today takes a different form.”

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