Nothing drains more your profit than wasted material after sheet cutting.
And nothing can be more frustrating than to see a huge pile of scrap increasing on the yard and being disposed.
These are real, tangible costs we can transform in earnings with little effort and creative thinking.
Here are some tips to start saving material.
1. Know Your Sheet Cutting Efficiency. It is amazing that nowadays, with all the available technology, many manufacturers do not know what is the utilization percentage of raw sheets after the sheet cutting in the shop.
They are not able to simply answer the question: how much of each plate is used effectively to produce the parts? or what percentage of the sheet becomes remnant.
Sometimes, you need to pick up a pen and paper and do some math to reach this number. It's okay if this is your case. At least it's a start. The best way to start making a better use of the material is to know what is the current waste.
When making an estimate, use a large enough period. At least six months or a year, to have a more real scenario. Remember that you can't change what you can't measure, at least when we speak of the waste of material.
2. Determine an Improvement Goal What would be a reasonable goal to achieve? If today you have a sheet cutting efficiency of 70%, it would be possible to reach the 80%? What would the economy be if we could get these 10% more.
It is important to know these numbers so you have a solid starting reference when speaking with the teammates and managers.. The waste reduction have the return calculated easily because it is something tangible and easy to note.
We recommend that changes be constant and gradual. Large impacts can ward off some people or be more complex to manage. A little more consistent improvement paves the way for other improvement projects.
3. Identify the Impediments for Improvement What prevents you from increasing the sheet cutting efficiency? Are there too large parts to fit into a single plate? Do you work with materials with grain that cannot be rotated? How long do you have to do the sheet cutting operation?. The change on fabrication priority makes your planning more difficult? Make a list.
4. Identify Opportunities for Improvement. Look for ways to reduce the cost of raw materials. Did you look at every opportunity? Can you reduce raw sheet stock and respond just in time to make cutting plans in real time? Would it be possible to buy less different sizes of sheets but in larger quantities and get a better price? Did you consider increase efficiency combining multiple fabrication orders at the same cutting list program?
5. use the Actual Dimensions of the Plates Every plate has a nominal width and length the vendor must ensure However ,in practice, sheets are slightly bigger. You can adjust the width and length to the real values.
Sometimes, a few more centimeters allow rearrangement of parts allowing more itens to be cut from the same plate.
6. Cut pieces Into the Holes The piece containing a hole has a "crumb" that can be used to cut a part. This is an invitation to increase efficiency. Take advantage of every chance you have to use the material that would become scrap.
7. Common Cuts If the sheet cutting allow placing parts with straight sides together, you can save not only material but also machine cycle time, because a single cut would be the same for two parts.
This type of cutting strategy is common and can save about 15% of a plate. It takes more attention when programming the cutting path (tool path) so that the pieces do not stand out from the plate before the correct time.
8. Extra Parts If you produce standard parts or maintains a parts inventory, maybe you can take advantage of each sheet containing some unused area to insert parts that will be used in the future.
There are some strategies to increase the chances of reuse these materials:
Alternative materials. If you are producing a more expensive parts, like stainless steel, you can use the room to spare with pieces that originally would be made with cheaper metals.
Even though it looks to be a waste, ultimately worth have more finished parts rather than scrap wasted.
Stock/Kanban. If you regularly produces a parts inventory, add them to the plans. So you keep stocks in appropriate levels without needing to cut plates just for this purpose.
The secret here is to trace and control inventory levels of each part to learn which parts should be included in your next cutting plane.
Future requests. The leftovers and scrap can be reduced substantially if we look to the future in the requests that have not yet entered into production and anticipate the production of some parts. As if anticipating the deadlines, this increasing the efficiency of the materials.
9. Applications Group The greater the diversity of parts, with different amounts and geometries, the greater the chances of the optimizer software find a better arrangement of the pieces, resulting in a better use.
To make this happen, you can combine different fabrication orders containing parts of various shapes. Make a cutting plane, see the results. Increase the amount of pieces, include more geometries and keep doing simulations to obtain optimal results.
10. Management of Remnant and Nesting A remnant is a huge part of material created after the sheet cutting. This leaves a negative account of utilization statistics.
Ideally, save and identify each remnant to be used in future jobs.
At the next opportunity, create a cutting plan with this material and remnant will be used to increase efficiency.
Remnant management usually involves a higher level of identification and traceability of materials, so it is recommended that you use identification labels as soon as possible.
Our experience with Optimize Nesting shows most companies that initially looks for remnant management, just realize the gains made with the nesting software are reduced so much that there is no justification for doing this.
That is it! If you follow the tips mentioned, each sheet plate will be used in its maximum.
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