Manufacturing invoice processing: how to automate it across plants and ERPs

 

Manufacturing invoice processing means capturing every supplier invoice, running the three-way match, sending exceptions to the right buyer, and keeping the full document trail ready for audit. In a manufacturing enterprise, that work runs across several plants and often several ERPs. Done well, it pays suppliers on time and keeps production supplied.

Done badly, it slows everyone down. According to the Atradius Payment Practices Barometer for the United States (2024), US companies name administrative inefficiency in their customers' payment processes as the main reason B2B invoices are paid late. In manufacturing, much of that inefficiency sits in the documents around the invoice.

This guide shows you how to automate invoice processing in a multi-plant manufacturing business, step by step, and how to carry the same approach over to customer orders.

Key takeaways

• A manufacturing invoice can only be approved as fast as its purchase order, order confirmation and goods receipt can be found
• Automating line-item capture and three-way matching lets clean invoices pass on their own, so your team works only on real exceptions
• One intake and one set of rules can serve plants that post to different ERPs, which matters most after acquisitions
• Filing each invoice with its document chain turns an auditor's question into a two-minute search
• The same capture approach works for incoming customer orders on the order-to-cash side

What is manufacturing invoice processing?

Manufacturing invoice processing is the workflow that takes a supplier invoice for materials, parts, freight or services from receipt to payment. It runs from capture and matching through approval to posting and retention. In manufacturing, partial deliveries, price adjustments and multiple plants make each of these steps harder.

Why manufacturing invoices stall before anyone approves them

Most stuck invoices in manufacturing are correct. They stall because the documents needed to prove them are somewhere else.

A blanket order for castings ships in several batches, and each batch arrives with its own invoice. A steel supplier adjusts the unit price between the order and the delivery.

Receiving books 478 units when the invoice says 480. Each case needs the purchase order, the supplier's order confirmation, the delivery note and the goods receipt side by side before anyone can approve payment.

When those documents live in an inbox, the ERP and a plant's shared drive, AP becomes a search team. The fix is to bring the documents together at the point where the invoice is checked.

How to automate manufacturing invoice processing in five steps

These five steps follow the invoice from arrival to archive. Each one removes a reason for the invoice to wait.

Bring every supplier invoice into one intake, whatever the plant

Supplier invoices reach a manufacturer as paper, emailed PDFs, EDI messages and e-invoices, and every plant has its own mailbox. Start by routing all of them into one intake, so every invoice is visible from the moment it arrives.

A single intake also gives you one place to set the rules for every later step. Your plants keep their own approvers and cost centers, and the process stays the same for all of them.

Capture line items as well as the invoice total

Header data tells you who sent the invoice and how much it is for. Matching in manufacturing happens at line level: part numbers, quantities, units and unit prices.

Automated invoice processing reads the supplier, invoice number, date and every line item, whatever the supplier's layout. Your AP team checks and confirms the extracted data, and nobody retypes it.

Match against the purchase order, order confirmation and goods receipt

Three-way matching compares the invoice with the purchase order and the goods receipt. When quantities and prices line up within your tolerances, the invoice moves to posting with no one touching it. Doxis AI.dp runs two-way and three-way matching as part of capture.

Price changes are easier to catch one step earlier. When your team checks the supplier's order confirmation against the purchase order, an agreed price increase is already approved by the time the invoice arrives.

The same check protects you against paying twice. Each new invoice is compared with the invoices already received, so a duplicate invoice with a slightly changed number is stopped before the payment run.

Send exceptions to the buyer with the documents attached

Some invoices will still fail the match. Invoice exception handling works when the exception reaches the person who can resolve it, with everything they need to decide.

Rules, for example by cost center, route each exception to the right buyer or approver automatically. The buyer sees the invoice next to the purchase order and the goods receipt, approves the price variance or rejects the invoice, and the decision is logged. AP stops chasing answers by email.

File the invoice with its document chain

Once the invoice is posted, it goes into the archive together with the purchase order, the order confirmation and the delivery note, all linked to the same record. Months later, anyone with the right access opens one record and sees the full story of the purchase.

In manufacturing, this is the step that makes every other step traceable.

Run one invoice process across plants on different ERPs

Many manufacturers run more than one ERP. A plant acquired three years ago may still post to Infor or Microsoft Dynamics while headquarters runs another system. Building a separate invoice process for each ERP multiplies the rules, the training and the audit work.

Doxis provides one process layer above your ERPs. Invoices from every plant follow the same capture, matching and approval rules, and the results are posted to whichever ERP that plant uses. Connectors cover common systems such as Infor, Microsoft Dynamics, Sage, and Oracle JD Edwards.

The process also survives an ERP change. Medical equipment manufacturer Dürr Dental in 2014 went live with automated invoice processing on Infor, and kept it running when the company later moved to IFS.

The same logic holds when your plants sit in separate legal entities, where multi-entity invoice processing adds entity-level approvals and posting. It is also one of the criteria that separate the AP automation software for manufacturing on the market.

Keep every supplier invoice audit-ready

An auditor's question about a payment comes down to three things: what was ordered, what was received and who approved it. When the invoice is filed with its document chain and every processing step is logged, you answer from one record.

US rules set the floor. The IRS links how long you keep a record to the period of limitations for the tax return it supports, and that period depends on the situation. For publicly listed manufacturers, the Sarbanes-Oxley Act adds requirements for internal controls over financial reporting, and approval logs can serve as evidence.

An archive built for this keeps records unaltered and retrievable for as long as they are needed, which is the core of audit-proof archiving in the US.

How Eissmann cut processing time per invoice by around half or more

Eissmann Group Automotive supplies vehicle interiors from 12 locations and employs 5,000 people. Its invoices were processed manually in separate systems, and any new process had to work across two ERP systems and several languages.

The company automated inbound invoices from capture through workflow-supported verification to audit-proof retention, and rolled the solution out to its sites in the US and Mexico. Up to 3,800 employees can take part in the approval workflow, each seeing only the invoices they are responsible for.

• Average processing time per invoice fell from 15 to 17 minutes to 5 to 8 minutes
• Daily volume grew from about 80 to 100 to 120 invoices, handled by the same team
• Every processing step is logged for audits

Extend the process to customer orders on the order-to-cash side

Your own invoices to customers are only as accurate as the orders behind them. When customer orders are keyed in by hand, every typo flows into the delivery and on into the invoice your customer disputes.

The capture approach that works for supplier invoices applies here too. Doxis captures incoming customer orders, checks the data with AI and passes it to your ERP through an open API. For companies on SAP, ready-made modules cover sales order processing and billing within the order-to-cash process.

SEW-EURODRIVE, a drive technology manufacturer with locations in more than 50 countries, processes more than 750,000 customer documents a year with Doxis AI.dp . Its team now handles far more volume with the same number of people and follows up on many more quotations.

Your AP team spends its days finding the purchase order, the delivery note and the buyer who can explain a price change. With Doxis, every supplier invoice arrives with its documents, clean invoices pass on their own, and each exception reaches the right person in every plant, whatever ERP that plant runs.

Invoice automation works best on a platform that also holds the documents around it. Intelligent document processing reads invoices, order confirmations and customer orders, and the Doxis archive keeps each record with its full chain for as long as you need it.

• One intake and one set of rules for supplier invoices from every plant
• Line-level three-way matching, so clean invoices post without manual work
• Duplicate checks against every invoice already received
• Exceptions routed to the right buyer with the purchase order and goods receipt attached
• Each invoice archived with its purchase order, order confirmation and delivery note
• Capture of customer orders on the order-to-cash side

In a Forrester Total Economic Impact study commissioned by Doxis, manufacturer SEW-EURODRIVE achieved a 336% ROI from automating its document-driven workflows with Doxis. Doxis is also named a Leader in the Gartner® Magic Quadrant™ for Document Management 2026. Request a free demo to see it with your own invoices.

FAQ about manufacturing invoice processing