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How integrating CAD and ERP drives improvement

Better data management leads to better productivity

Does your shop floor manager cringe at every announcement of revision changes or corrections to customer designs or drawings? Do your engineers sit around for hours every week writing new bills of material (BOMs) for those rev changes? Do drawing and material list changes almost always translate into production delays that lead to cost overruns and late deliveries?

CAD technology has revolutionized engineering and design, but delays still can occur in manufacturing because of the document change process, which in turn leads to cost overruns and missed due dates. That document change process inevitably involves making sure BOMs are current and correct. This can be a lengthy, tedious task, especially considering how large BOMs can get at certain companies.

Now, though, CAD software can work with enterprise resource planning (ERP) software. With the two integrated, a fabricator can simplify the process of building BOMs and improve their accuracy, and the new data can transfer directly to the shop floor via the ERP system. Establishing procedures and adopting technology to ensure that smooth transition between CAD and the BOMs in the ERP system can prevent a lot of headaches.

CAD Has Evolved

CAD programs make it quick and efficient to update drawings with other job-related documents. With sophisticated 3-D modeling programs like SolidWorks®, SolidEdge™, and AutoCAD®, engineers can dramatically speed the process of creating the drawings and designs required to manufacture complex parts and products. If an engineer makes a change to one component, the software detects interference and other design implications throughout the rest of the assembly. For instance, if that engineer changes the material thickness or the position of a sheet metal component, the software has the ability to detect the fact that certain hardware pieces don’t have enough threads to make a secure connection.

When those drawings need to be changed, CAD programs can simultaneously update every view of the drawings, thereby eliminating the time and expense of entering the data multiple times. However, transmitting these updates from engineering to the shop floor in a timely manner is where the delays, errors, and additional costs typically occur.

First, all BOMs related to the job have to be manually updated by engineers to match the current version of the drawing being distributed to the floor. Considering that engineering time is typically the most expensive of all labor costs, this can add significant costs to a project. Additionally, new plans need to be printed and distributed to everyone working on the job.

Delays also can occur when engineers make data-entry mistakes while manually updating the BOMs. If even one operator ends up working with an outdated version of the drawing, it can seriously delay or even derail an entire project.

About Traceability

In companies that have a structured engineering department (that is, more than one person), somebody creates the engineering change notification (ECN). This can come from various places, depending on the manufacturer and its organizational structure. It could come from production, if the change would solve a production issue; it can come from the head of operations in communication with customer service, which received feedback or complaints from customers; or it could come from the quality department.

Once an ECN is initiated, people must follow a structured process. Generally, it lands first in the engineering department, then operations, purchasing, and costing personnel. Then engineering performs any further modification, then the final sign-off. Once the sign-off occurs, the production control manager is notified.

If set up and integrated correctly, ERP systems have helped implement these ECNs efficiently by sending notifications to the right people at the right time, and asking for their input, review, or approval. This creates a digital record and helps simplify the ECN process compared to the old paper-based system, where ECN packets were passed around the office, spending hours or days in people’s inboxes.

The ECN procedure can vary depending on the type of manufacturer, but digitizing the process can help simplify matters immensely. Still, one manual step remains: manually keying in information to update the BOM.

And mistakes can happen, particularly when the fabricator has similar part numbers designating entirely different parts. In sheet metal fabrication, for instance, part numbers reflect specific characteristics, like material grade or gauge. This means that two different parts can have similar (though of course not identical) part numbers. One part may be of 12-gauge material, while another may be 16 ga. One job may call for 6061 aluminum, while another may call for 6063 aluminum, and another may be 5052. The chance for data-entry error abounds.

Then comes the issue of multilevel BOMs, which amplify the problem. With a single-level BOM, the fabricator makes one part, and every other component is purchased. Most fabricators manage multilevel BOMs, where the plant makes multiple parts that come together into a larger assembly, which can include parts made in-house as well as parts from an outside source.

Another way to look at it: A multilevel BOM has manufactured parts within a manufactured part. A completed assembly can have many levels to its BOM. It’s a bit like peeling back an onion. A final assembly has BOM levels associated with each subassembly, which in turn has BOM levels associated with each weldment, which in turn has BOM levels associated with each sheet metal part.

If a bottom-level BOM is updated, some companies update all BOM levels above it, so that everything reflects the latest revision date, even though most components may not change. Other companies update the BOM level only if changes are required. Whatever the method, making those changes in an established, documented process is critical.

From a data management perspective, software can now automate what was once a tedious, time-consuming, error-prone task of updating BOMs. Depending on the software platforms the fabricator uses, the communication between CAD and ERP can occur via a direct CAD plug-in or a simple export function.

After someone creates an ECN in the ERP system, that person can copy the BOM from the previous version to the new revision. When the new data from CAD comes into the ERP system, two BOMs appear on the ERP screen side by side, one before the revision and one after.

Different elements are highlighted in specific colors that show the changes the revision in CAD made to the BOM. The colors represent the kind of change made: a quantity or description change is, say, orange; removing an element from the CAD model is blue; adding a component to CAD is purple; and so on. The update happens immediately, no keying in required. This verification step can help when planning production to make sure everyone has what they need for the job to flow smoothly, from the receiving dock to the shipping dock.

It Starts With the Drawing

Designing in CAD and the BOM creation in the ERP are separate processes, and for good reason. The two systems should not communicate constantly. After all, you wouldn’t want a BOM to update every time an engineer makes a change to the CAD file.

The flow of information needs to be controlled by the established ECN process. Once the engineer is finished with all design changes, that person can initiate the export of information to the BOM in the ERP.

The flow of information occurs in one direction, from CAD to ERP, not vice versa. It isn’t a two-way street. This lessens the chance for errors and ensures that the solid model remains the “one version of the truth” for a job. Those drawings are the lifeblood of a manufacturing operation. If someone makes a change in the ERP system and not in the CAD file, which is the controlling data set?

If a drawing doesn’t match the information that’s going out to the shop floor, troubles arise. This ultimately leads to “knowledge silos” in which certain departments get a job done a certain way that’s not documented or based on the drawing. This in turn builds tribal knowledge, which isn’t sustainable in the long term.

How CAD Integration Works

When everyone on the shop floor has instant access to the latest BOM, and when the ECN process becomes paperless, the human error associated with paper documents and manual data entry goes away. It eliminates the time and cost of having engineers sort through the paperwork to identify the mistake. Orders move through the shop floor quicker and more smoothly. Keeping the BOMs accurate and current helps avoid material processing errors. And engineers can use the imported BOM to compare it to the material and inventory in the ERP system to ensure each job has the material required to finish production on time.

CAD and ERP integration involves two pieces. One piece resides within CAD so that the engineer can get the data out easily. The second piece is on the ERP side, which reads the information coming from CAD.

CAD interfaces are specifically designed to work with today’s manufacturing ERP systems. However, the process can vary depending on the type of CAD program being used. For example, with SolidWorks, the process uses the CAD program itself as the primary driver. Users build their BOM assembly in SolidWorks and then export it directly to the ERP. With AutoCAD, users build the BOM assembly in CAD and then export it with a comma-separated-value (CSV) file. They can also receive an Excel file directly from a customer and use Excel to convert it to a CSV. Once complete, they can import that file into ERP.

To implement this process and ensure CAD and ERP work together effectively, engineers need to know how to configure the data, how to structure the routers and BOMs within the ERP system, and how to use the CAD interface software.

To start, a template needs to be determined that establishes what CAD data will be pushed to ERP: the product description, the source (purchased or manufactured), lead time, the revision number, etc. Which to push depends in large part on shop practices. For instance, some operations don’t push the revision number to the ERP. In these cases, the latest “push” to ERP is the latest version, and all revisions before that are irrelevant and, therefore, hidden from view. Some shops, though, do want the revision number to ensure everyone is on the same page for a certain job.

The structure of the CAD model and associated BOM must mimic the way production operates. For instance, say the fabricator has a top-level BOM that shows all the hardware that connects the sheet metal assembly together. However, more than half of that hardware isn’t inserted during final assembly, but immediately after bending. That’s because those hardware insertion points couldn’t be accessed in final assembly. Before it gets to assembly, people in the shop have already inserted more than half of that hardware.

If the BOM structure doesn’t reflect this, people on the floor will need to hunt for what they need: search for the work order in final assembly, identify the hardware pieces they need, and retrieve the hardware—a tedious task that’s rife with error. And none of it is specified where it should be, in the local work order (with the lower-level BOM) that’s tied to the forming operation at the press brake.

This can skew job costing tremendously. The subassembly now costs less than it should, and it’s not just canceled out by the increased cost of the final assembly (which has more hardware associated with it than it should). With a flawed work order structure, operators need to spend time searching for what they need, and that time isn’t free.

The structure of the CAD model and BOM needs to reflect the reality of how the job flows on the floor. Specifically, the model should match the hardware that needs to be inserted after forming with a specific subassembly (not the final assembly) and with the lower-level BOM tied with that subassembly work order. This way, when the brake and hardware insertion press operator looks at the work order, he sees the hardware that needs to be inserted.

Essentially, having the right CAD model and BOM structure ensures that all work orders give operators everything they need to get the job done. In one sense, it’s like applying the 5S concept to the digital world of CAD and ERP. The “tools” in this world are data points (this hardware type, that material grade and thickness), and like 5S, these data points need to be organized and easy to find.

The Last Step

Testing is critical to ensure data flows correctly from CAD to ERP. This usually involves configuring the output from the CAD, pushing it into the ERP system, and validating that everything is appearing correctly. This can take several iterations, because naming conventions may differ depending on where the model comes from. For instance, someone may use structural weldment profiles in SolidWorks while another may not.

This also involves standardizing units. This doesn’t just involve imperial versus metric. It also involves establishing what baseline measurements are. Some operations have “one sheet” or “one extrusion” as one unit, which can create confusion should the size of the source material change. If one 18-ft. extrusion is considered “one stick,” a 9-ft. extrusion would be “one-half of a stick.” But what if the shop starts buying extrusions in 20-ft. lengths?

A shop may decide to change units of measurement to reflect how material is actually consumed, not how it is purchased: so instead of “one stick,” the unit would simply be inches; instead of “one sheet,” the unit would be square inches or square feet to match the baseline measurement of most nesting software.

Make Data Easy for the Shop Floor

Information from CAD and ERP needs to make it easy for the people on the shop floor. If it’s not easy, and if operators need to hunt for the right information, troubles will arise. This again gives rise to tribalism and knowledge silos. People find their own ways to get jobs out the door. Processes remain undocumented and nonstandard—a recipe for chaos.

Smart data management, starting in CAD and flowing seamlessly to ERP, helps modernize and simplify the manufacturing process. It reduces the amount of engineering time and expense in each job. It eliminates errors and rework caused by data-entry mistakes. And it simplifies document revision while making it more visual.

The bottom line: Using a CAD interface with an ERP can ensure data gets to the shop floor faster and more accurately and can generate a significant return on investment. Most significant, it can help improve the entire production process. After all, that is what ERP software is supposed to do—simplify manufacturing.