How to add document OCR to Plex Smart Manufacturing Platform
Short answer
Scan or receive documents into a capture service, run OCR and layout-aware extraction, validate against Plex data through its APIs, and send low-confidence fields to a human reviewer. Post only validated results and attach the source image to the Plex record.
A Plex plant still receives paper and PDF: supplier packing slips at the dock, mill certs, certificates of conformance, first article reports, inspection sheets from sub-tier processors, and signed travelers. Someone keys that into Plex or scans it and attaches it without reading it.
OCR on its own is rarely the problem. The value is in the checks after reading: does the part number exist, does the lot match the PO, is the quantity within tolerance, is the cert from an approved source. Those checks need Plex data, which you reach through its APIs.
This page lays out a capture path that suits a hosted system, with confidence thresholds and a review step so errors do not become inventory records.
What teams use it for
Dock receiving from packing slips
Photograph or scan a packing slip; the service reads PO, part and quantity, matches to open PO lines, and prefills the receipt for the receiver to confirm.
Certificates of conformance and mill certs
Extract heat or lot numbers, material spec and certification statements, then attach them to the received lot for quality review.
Supplier invoices to a draft payable
Read invoice number, totals and lines, then do a three-way match against PO and receipt before queueing for payables.
Inspection and first article reports
Read dimensional results from structured forms and compare to specification limits before filing against the part and lot.
Legacy paper traveler digitization
Scan completed paper travelers for lines that still run outside Plex, and attach the extracted sign-offs to the job record.
Drawing title block indexing
Read part number, revision and drawing number from title blocks to file incoming drawings against the correct part revision.
Plex Smart Manufacturing Platform integration surface
- Plex REST APIs and Data Source API (DSAPI) to validate extracted values against parts, POs, receipts, suppliers and lots; names vary by release.
- Plex receiving and purchasing screens or APIs for creating a receipt; whether you can post receipts via API depends on your tenant, so confirm before building.
- Plex document attachment capabilities for storing the scanned source against a PO, receipt, lot or part; check API availability in your version.
- Plex supplier and part master data, including supplier part numbers and approved sources, which drive validation rules.
- Capture side: network scanners, mobile camera, a watched folder, or email intake feeding the OCR service.
How it works
- 1
Choose capture points
Pick where documents enter: dock scanners, a mobile app, a scan folder or the shared mailbox. Standardize resolution and orientation guidance for each.
- 2
Select OCR and extraction
Use a layout-aware engine or a vision-language model. For controlled documents, choose an engine you can run locally.
- 3
Define fields and validations
For each document type list required fields and checks, such as PO exists, part on PO, quantity within tolerance, lot format valid.
- 4
Score confidence per field
Route any field below its threshold, and any failed validation, to a review screen showing the image crop beside the value.
- 5
Post and attach
On approval, call the Plex API to create the draft transaction or update the record, and attach the original with a hash.
- 6
Learn from corrections
Store reviewer fixes to adjust supplier-specific rules and to measure error rates over time.
Example flows
Packing slip to receipt draft
Trigger: A receiver scans a slip at the dock.
- OCR reads PO number, part, quantity and lot.
- Service fetches open PO lines from Plex and matches.
- A quantity above the open balance is flagged.
- Receiver confirms or corrects, then submits.
- The receipt is created and the slip is attached.
Result: Fewer keying errors at receiving and an image tied to every receipt.
Cert review for a lot
Trigger: A mill cert PDF arrives with a shipment.
- Service extracts heat number, spec and chemistry.
- It compares the spec to the part's material requirement.
- A mismatch routes to quality with the page highlighted.
Result: Certificates are checked against requirements before material is released to the floor.
Keeping data on-prem
Plex is hosted, but the documents you scan are often the most sensitive thing in the chain: drawings, certs and customer specifications. Run OCR and any vision model on-prem or in a private cloud on your own GPUs, keep images in storage you control, and send only validated field values plus a reference to Plex. This keeps the architecture compatible with whatever your obligations are around controlled data, though the determination of what may leave your boundary is yours and your compliance team's. Air-gapped plants can run the entire capture stack offline and sync results to Plex through a controlled transfer point.
Security checklist
- Encrypt scanned images at rest and limit access by role.
- Hash each document and store the hash with the Plex transaction for tamper evidence.
- Keep reviewer corrections logged with user and time.
- Do not send drawings or customer specifications to public OCR or vision APIs without approval.
- Apply retention rules, since cert and receiving records often have long mandated retention periods.
Ways to get it done
Cloud intelligent document processing service
Effort: Weeks to configure, per-page pricing.
Non-sensitive invoices and standard forms at volume.
Open-source OCR plus local model
Effort: More engineering, full control over data.
Controlled documents and plants that need on-prem processing.
Partner implementation
Effort: Pilot with one supplier set and one document type.
You want validation rules tied to Plex data and a reviewer interface built for the dock.
Pitfalls
- !Skewed phone photos and low-resolution scans cut accuracy sharply; enforce capture guidance.
- !Handwriting and stamped overlays defeat generic OCR, so expect higher review rates there.
- !Supplier part numbers rarely equal your part numbers; you need the cross reference.
- !Setting thresholds too low pushes bad data into receipts, too high floods reviewers.
- !Multi-page documents with mixed types need splitting before extraction.
Frequently asked questions
Does Plex include OCR?
I cannot confirm general purpose document OCR as a standard capability, and it may vary by module and release. Plex can store attachments and accept transactions via interfaces, so OCR is typically a separate capture layer that feeds Plex.
What confidence threshold should we use?
Set it per field, not per document. Identifiers such as PO and part number deserve a high bar because errors are costly, while free-text descriptions can be looser. Tune from reviewer correction data rather than guessing.
Can OCR create receipts automatically?
It can, but start with prefilled drafts that a receiver confirms. Automatic receipts make sense only after a supplier shows consistently clean reads, quantity within tolerance and no exceptions over a sustained period.
How do we handle drawings?
Index title block fields for filing, and keep the drawing itself in controlled storage. Do not try to interpret geometry with OCR. If dimension extraction is needed, treat it as a separate project with human verification.
Where does an LLM fit?
A vision-language model can read messy layouts and reason about mismatches, then output structured fields for validation. Running it locally keeps document content inside your boundary, and the Plex checks remain deterministic code.
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