Purchase MRP
Purchase-manufacturing integration with automatic purchase orders from BoM and production needs
The Purchase MRP module tightly connects purchasing with manufacturing, automatically creating purchase requests based on Bill of Materials and production plans.
The system analyzes production needs, checks inventory, and automatically creates RFQs for missing components, ensuring uninterrupted production.
Key Features
Key points
• Auto-purchase from BoM: Automatically create RFQ when confirming manufacturing order based on BoM
• MRP Scheduler: Run MRP to calculate component needs and create purchase orders automatically
• Reordering Rules: Set minimum stock levels, automatically create RFQ when below threshold
• Lead Time Management: Calculate delivery times to order at the right moment
• Multi-level BoM: Support multi-level BoM, automatically calculate sub-component needs
• Vendor Selection: Automatically select vendor based on price, lead time, priority
• Purchase Forecast: Forecast purchase needs based on production plans
• Component Tracking: Track components from purchase order to manufacturing order
MRP Purchase Workflow
Steps
1. Set up BoM: Create Bill of Materials for product. Add required components with quantities. Select "Buy" route for purchased components.
2. Configure Reordering Rules: Go to Inventory → Configuration → Reordering Rules. Set Min/Max quantity for components. Select "Buy" route.
3. Create Manufacturing Order: Create MO for product. System checks component inventory. If insufficient, automatically creates RFQ.
4. Run MRP Scheduler: Go to Inventory → Operations → Run Scheduler. System analyzes all needs, creates RFQ for missing components.
5. Process RFQ: Review auto-created RFQ. Select vendor, confirm to PO. Track delivery.
6. Receive and manufacture: Receive components to warehouse. Start production when components available.
MRP Configuration
Key points
• Product Routes: Set "Buy" route for purchased components, "Manufacture" for manufactured products
• Vendor Pricelists: Import vendor price lists for components, system automatically selects best price
• Lead Times: Configure Purchase Lead Time (delivery time) and Manufacturing Lead Time
• Safety Stock: Set safety stock to buffer for demand variations
• Procurement Groups: Group RFQs by MO or project for easy tracking
• Automatic Ordering: Enable automatic PO creation when running scheduler (no RFQ confirmation needed)
Real-World Scenarios
MRP Applications
| Scenario | Configuration | Result |
|---|---|---|
| Make-to-order production | Create MO from Sale Order. BoM has components with "Buy" route. Run scheduler. | System automatically creates RFQ for missing components, ensures on-time production. |
| Batch production | Create multiple MOs for same product. Run scheduler once. | System consolidates component needs, creates combined RFQ, saves costs. |
| Multi-level components | BoM has sub-assemblies that also need purchased components. Multi-level BoM. | System calculates needs at all levels, creates RFQ for all required components. |
| Automatic reordering | Set Min=100, Max=500 for component. Scheduler runs daily. | When stock < 100, automatically creates RFQ to restock to 500, never out of stock. |
| Purchase by lead time | Component has Purchase Lead Time = 7 days. MO needs on day 20. | System creates RFQ on day 13, ensures delivery in time for production. |
| Automatic vendor selection | Multiple vendors for same component. Configure priority by price. | Scheduler automatically selects vendor with best price, creates RFQ. |
MRP Optimization Tips
Key points
• Run Scheduler regularly: Set up cron job to run scheduler daily or weekly to update needs
• Configure accurate Lead Times: Record actual vendor delivery times for accurate forecasting
• Use Safety Stock: Add 10-20% safety stock for critical components
• Group RFQs by project: Use Procurement Groups to track costs by project
• Check Forecast: View Purchase Forecast to predict next month purchase needs
• Optimize Min/Max: Adjust Min/Max based on consumption history and lead time
• Vendor Backup: Configure multiple vendors for critical components to ensure supply
Troubleshooting
Common MRP Errors
| Error | Cause | Solution |
|---|---|---|
| No automatic RFQ creation | Wrong route, reordering rule not configured | Check product route has "Buy". Create reordering rule with "Buy" route. |
| RFQ created with wrong quantity | Wrong BoM quantity, unit of measure mismatch | Check BoM quantity. Ensure UoM consistent between BoM and purchase. |
| Scheduler not running | Cron job disabled, permission error | Check Scheduled Actions in Settings. Re-enable cron job. |
| Wrong lead time | Purchase Lead Time not configured | Enter Purchase Lead Time in product form or vendor info. |
| Vendor not selected | No vendor info, pricelist not updated | Add vendor to product. Update vendor pricelist. |