This article looks at waste and material management in wire and cable manufacturing. It defines material waste and how excess waste production and inefficient material management can impact the bottom line.
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Examples of controlling material waste are highlighted, allowing readers to identify opportunities throughout the production process to make improvements.
The article highlights how software can help with material management and reduce waste, examining:
It might be obvious, but it’s a crucial point to begin this article: material waste costs money. For example, raw materials typically form 70%-80% of the selling price for wire and cable products. But in wire and cable businesses, the world of cash and finance can be dislocated from the business functions that determine how much material is wasted.
Waste may be hidden in:
Visible waste — the material that ends up in skips — is evident to all. Still, even there, costs can be hidden if the segregation and separation of materials to improve the value of scrap or facilitate their recycling are not taken into account.
Material cost considerations need to be assessed at each of the decision points that determine or affect how much and which types of materials are to be consumed.
Material waste is the cost of any materials consumed in excess of what is required to satisfy a customer’s minimum requirements. Some examples of material waste are:
When a specified material costs more than assumed in the costing exercise, a material price variance is not waste. Some commercial contracts will allow for variation in some materials, e.g., metals. The costs of non-metals, e.g., polymers, may be flexed less frequently based on oil prices.
To control something, it needs to be measured, then analyzed, and finally, action needs to be taken. To be most effective, actions must occur as close to the moment of conversion or usage of raw materials as possible.
Consider the value chain of a wire and cable business:
A customer may quote a specific national or international standard that has to be followed by the designer: there may also be additional customer requirements. Standards typically draw on the nominal dimensions of the different components from which a cable is formed. Standard geometric formulae established over many years are used to calculate the size, volume and weight of a cable’s components.
A designer must ensure that the final design is fit for purpose. Ultimately a cross-sectional drawing or 3D representation of it can be produced along with charts of dimensions and the standard weights per unit length of its components and hence the weight, and length, where relevant, of the raw materials. This can then be costed per unit length.
Businesses have an opportunity for competitive advantage when designing cables: exploiting a high degree of internal process capability. For example, a business with excellent statistical control of its processes knows how much material it needs to use to achieve a specific physical, electrical or optical parameter and can design toward the theoretical minimum.
Cable designers may interpret specifications differently, could apply formulae differently, and could, therefore, produce unnecessary design variants. Variants in dimensions of raw materials, e.g., tapes, dimensions of sub-components, e.g., insulated cores, usage of polymers, e.g., different grades of PVC, all add complexity and variety, which can embed waste in a business.
Cable design policy should be clearly defined for a business, whether single or multi-site and cable designs should be held in databases. Standard raw materials and sub-components should be stored in the database and shared with the business’s enterprise resource planning (ERP) system.
A costing needs to be calculated on the latest costs for raw materials or if any are known to be changing the future cost. Prices for raw materials for wire and cable do move up and down with commodity prices, and sometimes these changes are managed contractually. A cable business can choose to pass on price increases or hold prices. This should be driven by policy.
Costings also typically include allowances for scrap. These are generally derived empirically over the years and are applied as a percentage, e.g., 2%. A business knows that whatever the standard weight of cables, an allowance of an additional 2% has been added to allow for scrap, as, historically, that has been the overall weight of scrap measured across weigh-bridges in skips versus the weight of materials procured.
In addition, there may be an extra allowance for over-usage (sometimes called “giveaway”), or just loss, based on mass-balance calculations. A mass balance compares the quantity of raw materials procured versus the quantity of finished cable sold, adjusted for changes in intermediate and finished product stocks.
Design parameters are communicated to production and quality control staff via job cards, specification sheets, and, if the business can, electronically via business and manufacturing execution systems (MES). In addition, direct communication of cable design criteria and process settings may be downloadable to process machinery via integration with PLCs.
The supervisors and operators often manage the selection of raw materials and semi-finished products for input into a manufacturing process. For example, they may be working on an instruction about which specific drums and batches to draw from stock or, if a Kanban is being used, one chosen from any number of options.
It is also possible via barcodes to ensure that pre-defined raw materials and sub-components are selected to provide traceability and error-proofing.
An operator sets up their machine with the correct materials and process settings. Some machines have inherent waste associated with their design. This is a known quantity, or length, e.g., 10m, and is allowed for in the process design and the costing. Where good practice allows, a skilled operator may operate with less waste than that costed, but he should not produce excess waste. The waste becomes evident in inter-process skips as short lengths are scrapped, tape reels are emptied, extrusion head waste is weighed and skipped, or off-cuts are created at the final winding and testing stage.
There are measurement gauges of some form on most production lines, diameter, eccentricity, spark testers and capacitance. These may be purely for measurement or feedback signals to the machine controller so that process parameters are tuned to achieve target dimensions. Without automatic feedback, the operator must be more vigilant and adjust when necessary.
Gauges may be attached to a logger that records data through a run. This may produce statistical data such as averages and standard deviations and out-of-tolerance data such as thin walls or under or over diameter. However the data logging is completed, a quality record for each sub-component and each finished reel should be maintained. Any out-of-specification material will require a review by quality control to ensure the correct sentencing. Non-conforming products may become scrap or could be reworked. Such rework may involve the time-consuming removal of a layer and rewinding operations before repeating an incorrect process. This is expensive and may lead to short lengths. Rework can be a costly and hidden cost.
A statistical analysis regime can be applied to cable-making. This can lead to a good understanding of process capability and opportunities to shave off microns from designs that can lead to better material utilization and improved competitiveness.
Managing length is a hugely important aspect of good material usage. As cables progress through a factory, they get bigger — it’s a fact — as do the drums they are on. So ensuring that the lengths of finished cable produced are as close as possible to that required by customers, or included in catalogs, is one of the most critical factors in conserving materials. For example, an odd 20m length of good product at the end of a 500m order for a customer gives a potential 4% loss.
Managing drum stocks to minimize waste is vital for businesses that cut custom cable lengths from stock. Knowing the actual remaining length of cable on drums and fulfilling customer orders in a manner that minimizes short lengths reduces waste.
The easiest way to manage waste is not to make it in the first place! However, waste does occur. Recycling waste within the factory reduces the material cost impact of waste. Re-granulating extrusion head waste and re-feeding it into an extrusion run are commonly used. Re-granulating off-line and reusing later, e.g., polyethylene sheathing or re-compounding polymer by mixing with a black masterbatch, is employed to produce bedding layers for armoring.
Segregating different waste streams, e.g., keeping copper-related waste separate from aluminum or steel or keeping polymer or poor conductor waste separate, can improve the value of waste. Poor waste management could cost 0.5%-2% of top-line sales value, which comes straight off the bottom-line profit.
Waste can be minimized by maintaining designs at the lower end of tolerances in factories that exhibit good process capability and control. Operators must ensure that their processes operate within tolerance, preferably in the bottom quartile band. They must take care to use the specified materials and only start to convert materials when their processes are fully ready. All necessary steps should be taken to avoid making non-conforming products, and if there is any uncertainty, help, and advice should be sought. Supervisors should focus on quality and waste before productivity and delivery performance — poor quality decimates results on all other measures.
Businesses should know the quantity and source of all material waste and its cost. Projects to correct common root causes should be set up regularly, and their outcome should, wherever possible, eliminate the root cause of issues.
An oft-missed opportunity is the reverse-engineering of a business’s products and those of its competitors. Dissecting cables, comparing the different layers in the construction, and assessing any differences in design or manufacturing provide valuable intelligence. Design, materials, and processes are constantly changing. Maintaining a historical database of comparisons can provide short-term improvements and enable any changes in competitors’ samples to be spotted.
The volume of parameters that affect quality and waste is high, and the business processes that affect waste across all business functions. Therefore, managing data in a business-wide system and database is almost a prerequisite for larger sites and businesses. Data shared throughout a business and used in a standard manner provide a foundation for quality. They should form the basis of a long-term strategy for minimizing waste and keeping it under control. Using systems to provide feedback loops at the point of selection, consumption, and conversion of raw materials and semi-finished products reduces the chances of error and corrects usage for variations. Independent quality control and statistics provide the required checks and balances and information for targeted improvements.
Ensuring the value of different waste streams is known by the relevant staff, and reinforcing it, should be one of the critical activities of a management team. It is one of the main levers they can pull to maintain and improve profitability.
Designed specifically for the wire and cable industry, CableMES leverages the power of the world-leading System Platform by AVEVA, which brings reliable and flexible technology and utilizes the extremely powerful Historian tool capable of collecting any process data.
Users can correlate this data with process and quality alarms to an exact length of cable produced to identify trends and provide long-term improvement benchmarks. Historian and CableMES come with a wealth of reports which allow management to take a strategic view of the business and to drill down to the cause of any event.
As well as the savings in waste, cost reductions from CableMES can often come from making more efficient use of existing employees’ time through automated reports, accurate data handling and sign-offs.
Consider the costs associated with discovering non-conformance too late. The scrappage of an entire reel would be costly enough. Added to that the outlay of rearranging shipping as well as committing machines and operators to a second run and the cost rises exponentially. CableMES early warning system flags any such warnings at the earliest stages of the production process.
With increased competition, the margin for profitability may already be slim, and a manufacturer can ill-afford any issues that add to the cost of sale through rework or late delivery penalties. Without an MES, the production team has little opportunity to identify non-conformance issues until later in the process and sometimes only after a product has left the building.
Along with its non-conformance alerts, CableMES’ prioritization of Work in Progress (WIP) allows the factory to concentrate efforts on the most time-critical and profitable production, easily identifying bottlenecks, maintenance issues, under-utilized resources and hidden capacity. CableMES also ensures full accountability for all shifts ensuring seamless shift handovers.
Quality benefits gained from CableMES:
Ordering too much stock presents an issue for storage and cash flow; too little and there’s a risk of running out and reneging on customer delivery commitments. CableMES knows what material needs to be used for the production of a particular operation.
Each material to be used is scanned using a barcode scanner. The items going into the machine are matched against those in the bill-of-material (BOM), enabling products to move through the production process as quickly and efficiently as possible while maximizing labor and machines.
CableMES’ real-time stock inventory is compelling enough. Yet coupled with theoretical vs. real analysis on material consumption and machine speeds, it provides the production team with their greatest insight yet into capacity planning.
The easiest way to manage waste is not to make it in the first place. Material waste is the cost of any materials consumed in excess of what is required to satisfy the customer’s minimum requirements.
Wire and cable manufacturing will inevitably incur costs attributed to waste. However, appropriate systems, processes, and procedures must be implemented to minimize this waste and manage materials much more effectively.
A thorough understanding of the customer’s design requirements and specifications is needed to filter down to ensure accurate design and costing processes. Over-specified designs and the subsequent inefficient purchasing add unnecessary costs. For example, visible scrap from oversized or over-length products is costly. Still, the hidden costs of not managing and calculating waste segregation and separation procedures before recycling are factors that should not be ignored.
Measuring and analyzing all production elements will help monitor material usage and identify areas for improvement.
Effective communications across departments ensure design parameters are adhered to at every stage, and gauges to help tune parameters to achieve target dimensions ensure accuracy.
Conserving materials can be achieved by carefully managing length. For example, lengths of finished cables should be as close as possible to that required by the customer or included in catalogs.
Jul. 13, 2021
We have received many letters from readers asking some questions in the last couple of weeks, some of them look like 'fresher’, But some of their questions surprised us a little bit. In addition, we have also done research online to write this post, hoping to help readers or new buyers.
The electrical conduit is designed to protect wires because the wire is fragile, and there are will cause safety risks after damage. However, there are different sizes and names for different countries and markets, which makes it easy to confuse especially new buyers. In addition, the industry itself has a lot of professional vocabulary and certification standards. For new buyers, We strongly recommended you find a reliable supplier who can avoid many problems. For example, Ctube.
One more thing, we wrote a post for talked about conduit pipe & fittings type on the market last month. You can read the post here for the type of conduit & fittings and how it works.
Ok, let's get started.
Sunlight PVC pipe used for outdoor project purposes in general.
Well, there are many outdoor use scenarios, such as you need to run wires to your tool room, or install solar energy equipment. Because these wires and tubes need to be exposed to sunlight for a long time, and they are attacked by high temperatures, water, dust, and even temperature sharply drops at night, the performance of the wire and tube at low temperatures needs to be considered.
If you use an ordinary PVC electrical conduit, what will happen? The most common problems are yellowing, brittleness, and cracking of your wires tubes. This kind of line tube is usually white in color. Because they are NOT designed to be used as electrical conduits (usually for plumbing water pipes), they cannot protect your electrical wires under long-term exposure conditions.
From the perspective of product manufacturing, general electrical PVC wiring pipes, especially those with UV protection wiring pipes are generally in gray. And It has a different additive formula in the production process between ordinary PVC wiring pipes, so it is far superior to white PVC pipes in terms of UV protection.
In addition, there are differences in low temperature and waterproof performance. Specific data need to refer to the standards of each country. For example, you can check our Schedule 40 PVC pipe product page to get details for this.
No, you need to consider the US National Electrical Code requirement for all components of electrical installations need to be approved national test agency. So we do NOT recommend white PVC for electrical wiring pipes.
In addition, electrician wiring pipes are slightly different in formula and manufacturing process compared to water pipes. The thickness and diameter of electrical line pipes have strict industry standards, not just to unify one size. Electrician conduit can prevent overload and high current in an instant, also it has a higher fire rating. We even have low-smoke halogen-free ( LSZH Electrical PVC Conduit ) PVC pipe, the flame retardant grade is highest ( V0 grade fire rating, it will self-extinguished in 5 seconds after the cut off the fire sourcing ), and it can emit less smoke when burned compared with white PVC conduit avoid to release of toxic halogens to increase the survival rate of rescue operations. These are the test standards and content that ordinary drain pipes missing.
So for your safety, we do not recommend you to do this.
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Firstly, we do not think the color is the first consideration in your purchase decision.
But in fact, color does represent the difference in product application to some extent. For example, the anti-UV conduit pipe we mentioned earlier.
So we take Schedule 40 and Schedule 80 PVC pipes as an example.
These two pipes are just a standard. The most critical parameter is thickness. Schedule 80 is much thicker than Schedule 40 PVC pipe, and Sch 80 pipe is gray or dark gray in general. Sch 40 PVC pipe is white compared with the same period, and the thickness is thinner than Sch 80 PVC pipe.
So it is obvious from the comparison of the two parameters. Schedule 40 PVC pipe can be considered for home improvement or indoor decoration, while Schedule 80 PVC pipe is much stronger, so it can be considered for outdoor projects.
From the manufacturer's view, PVC was originally a very stable raw material, and its color was white. The gray color is caused by the special formula additives dying in the later period. These additives greatly enhance the high-temperature resistance of PVC and make the current conductivity weaker, so it can withstand Shocking thousands of volts of instantaneous voltages.
Of course, the color is not the standard. The most important thing is to see the body printing of the tube to identify the purpose before buying. It is the most reliable.
Of course. The National Electrical Code requires all of the conduit connections must to be tight. As to the PVC conduit pipes, it means glue.
Using glue to glue electrical pipes is the same principle as we glue other things, and the DIY is not difficult.
As a manufacturer, we do our best to control the tolerance range of each wire pipe size and strive to ensure compliance with relevant international standards, such as UL651. But the actual situation is that in the case of invisible to the naked eye, even on the same production line, there will be certain tolerances for PVC line pipes produced at different periods, which is inevitable.
Then, there will be extremely tiny gaps between the pipe to pipe or fittings, and between the pipe and the fittings. The role of glue is to fill these gaps, so the water, cement, and dust can hardly enter the inside of the pipe through such gaps,
Moreover, the glue itself has the effect of adhesion, which can increase the strength of the joint, and it is not easy to fall off. Of course, the fundamental purpose of doing this is to protect the wires inside the line pipe from being easily affected by these impurities.
Pro Tips,
(1) Professional PVC glue must be used instead of ordinary glue. Because PVC glue has high adhesion strength and resistance to high & low temperatures, water, etc, all of these features not available of ordinary glue;
(2) Glue can be evenly applied to the connecting part of the male connector of the pipe, and the female connector can be applied a little bit. After coating, insert the male head into the female head, insert it in a slightly rotating manner and reach the right position to ensure that the glue is in full contact;
(3) It is best to use a small brush to apply the glue. It does not need to be applied too thickly, just a thin layer, otherwise, the glue will overflow.
(4) PVC glue usually takes 1-2 hours to fix, reaches the ready to use after 24 hours, and reaches the best adhesion strength after 48 hours.
First of all, in addition to the PVC electrical conduit and the electrical box, you also need to prepare an adaptor with locknut and PVC glue.
As for the installation method, so easy. The first step is to glue the pipe to the adaptor, remember to use glue, and your can reference our previous Pro Tips content about glue conduit pipes. The second step is to insert the threaded part of the adaptor into the electrical box, and then lock it with the locknut. Of course, you can also add a little glue to the locknut part, which is more firm and reliable, and it is also the simplest way of waterproofing.
Of course, if your electric box is integrated with fittings, then you can directly apply glue to the wire tube and insert it into the electrical box.
In addition, if the flexible pipe needs to be connected to the electrical box, you just follow the above steps, the only difference is you need to pick up another adaptor used for flexible pipe for the locking part is needed to fix the flex pipe end.
I believe you will know how to connect through the pictures.
6.Why can't PVC be recycled?
This is an incorrect question because PVC can be recycled, but the recycling cost is too high.
PVC, like other plastics, is often accompanied by many impurities after being eliminated and used, and it needs to be sorted before it can be recycled. The early physical recycling and burning recycling methods have been eliminated. The quality of the plastic materials recycled by the former is not good because it is difficult to sort. The latter is harmful to the environment because many harmful gases are released during the burn of PVC to pollute the environment. Therefore, at present, only chemical recycles methods can be used to do this. Chemical recycles can get higher quality recovery, but the cost is high.
BTW, the recent crazy increase in crude oil prices has greatly affected the prices of plastic raw materials, so recycling is a trend in the future.
Secondly, the quality of recycled PVC is not as good as that of brand new materials. So it can only be used for some low requirement applications, such as shoe soles, agricultural drainage pipes, and so on.
From the electrical PVC pipe industry, recycling has another meaning. What we call Recycling Materials usually means that after the first injection or extrusion, there may be some quality issues that may cause the product to be scrapped. To not waste raw materials, the process of mixing these raw materials back into use is called recycling. It has a different meaning from the recycled raw materials above and can be said to be the raw materials for the second processing.
Of course, what is described above is an ideal situation. If the raw materials are only circulated in the factory, it should be better. Some factories buy this kind of recycled materials and mix them with a certain proportion of brand-new materials, so you can't distinguish it in appearance, but its physical properties are much different from those made of 100% brand-new materials. This is why Ctube insists on using brand new materials during the 10+ Year production process. It can be said that we have never been complained by customers in this regard.
No, you can't. NEC general sets a minimum separation of 2 inches between communications and electric power cables. In addition, for security purposes, this is not a best practice.
There are 2 key points here. The first one is that the ethernet cable is a signal wire, and the current is weak, and there is a possibility that the signal will be interfered with by a strong current one. Then the performance of your network signal is unstable, there will be irregular interruptions or high data transmission delays, which will affect your experience.
The second one is the wire generally has a relatively large current and the temperature will be higher. If an accident occurs, the large current may directly cause an instant short circuit of the wire, and at the same time, it will be transmitted to the ethernet cable and affect your terminal equipment (such as routers), resulting in damage to your terminal equipment.
So we suggest that you need to run these two wires separately. Common power wires are installed through one pipe, while ethernet cables are installed through another pipe. And through accessories such as bend, they can be installed from two different positions. which can increase signal stability and safety.
This is a broad question because we don’t know exactly the purpose of the reader. So we only talk about our area. Yes, that’s an electrical conduit pipe.
Firstly is the material, we think PVC should be a smart choice. As we mentioned before, PVC material, especially the current high-quality raw materials can hold the instantaneous voltage shock of several thousand volts, and it has many advantages such as anti-rust, waterproof, and UV resistance.
Secondly is checking the parameters. Generally, household wires will have cable diameter data, and run the 2-3 ways is in one electrical conduit is no big problem. So you need to pay attention to inner diameter and thickness when buying the wire pipe. Generally speaking, the inner diameter of the purchased wire pipe must be larger than the sum of your wire diameters, and extra space can be reserved for future upgrades or replacements.
Finally, choosing a reliable brand is very important. Brands such as Charlotte Pipe or Carlos are more reliable in the US because they have many years of experience and relevant certification. We suggest that you can buy directly from their official channels or distributors. There are also customers asking whether we can buy on Amazon? We think that Amazon may be more professional in the field of e-commerce, but they do not understand and doing great about quality control of products such as electrical pipe, so we do not recommend buying on an e-commerce website such as Amazon.
Does an outdoor electrical wire need to be in a conduit?
Absolutely!
As we mentioned before, the wiring runs outdoor, it will not only be exposed to sunlight direct in a long-time, but also will be affected by factors such as low temperature at the night, water, dust, even wild animals.
If the wire is damaged, it will not only waste your time to repair it. Moreover, damaged wires may cause a safety accident, which is dangerous.
Some of our customers also told us that the wires they laid out would not be exposed to sunlight, but we mentioned that there are other reasons. We need to know that the insulation layer of the wire itself is thin, so it has the limited protective ability. So we still recommend installing electrical conduits.
Whether it is directly buried underground or run wires on the ground, you should place them in the wire tube to provide better protection for safety.
This question is not difficult to answer, just use the conduit fittings, such as bend or elbow.
We have seen that many construction workers use springs or hot air guns to bend pipes in the actual construction process, which is not the best practice. Let's take an example. You can take a bottle of Coke and pinch the middle of the plastic bottle with your hands. You will find that there is less Coke in the middle because they are under pressure and flow to both sides. The same is true for spring bending. The density of PVC electrical pipe is a fixed value. Even if you bend the pipe with spring, it looks no problem to the naked eye, but its strength has changed, just like the Coke bottle, the Coke becomes less already, so the strength of the wire pipe itself is reduced.
Therefore, this problem can be easily solved by using a bend or elbow with an angle of 45° or 90°, and you do not need to worry about the strength of the conduit pipe.
You can also refer to the Fittings Post we wrote earlier, or check our Fittings product page, you will have a clearer understanding of how they work.
That's it, thanks for your reading. You can contact us and leave your message to let us know what your problem is, we will reply to you shortly.
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