diff --git a/src/Services/EntityMergers/Mergers/EntityMergerHelperTrait.php b/src/Services/EntityMergers/Mergers/EntityMergerHelperTrait.php
index bdc18bac..2eb3ff88 100644
--- a/src/Services/EntityMergers/Mergers/EntityMergerHelperTrait.php
+++ b/src/Services/EntityMergers/Mergers/EntityMergerHelperTrait.php
@@ -23,6 +23,11 @@ declare(strict_types=1);
 
 namespace App\Services\EntityMergers\Mergers;
 
+use App\Entity\Attachments\Attachment;
+use App\Entity\Attachments\AttachmentContainingDBElement;
+use App\Entity\Base\AbstractStructuralDBElement;
+use App\Entity\Parameters\AbstractParameter;
+use App\Entity\Parts\Part;
 use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Collection;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
@@ -153,9 +158,12 @@ trait EntityMergerHelperTrait
      * @param  object  $target
      * @param  object  $other
      * @param  string  $field
+     * @param  callable|null  $equal_fn A function, which checks if two items are equal. The signature is: function(object $target, object other): bool.
+     * Return true if the items are equal, false otherwise. If two items are equal, the item from the other collection is not added to the target collection.
+     * If null, the items are compared by (instance) identity.
      * @return object
      */
-    protected function mergeCollections(object $target, object $other, string $field): object
+    protected function mergeCollections(object $target, object $other, string $field, ?callable $equal_fn = null): object
     {
         $target_collection = $this->property_accessor->getValue($target, $field);
         $other_collection = $this->property_accessor->getValue($other, $field);
@@ -167,6 +175,19 @@ trait EntityMergerHelperTrait
         //Clone the items from the other collection
         $clones = [];
         foreach ($other_collection as $item) {
+            //Check if the item is already in the target collection
+            if ($equal_fn !== null) {
+                foreach ($target_collection as $target_item) {
+                    if ($equal_fn($target_item, $item)) {
+                        continue 2;
+                    }
+                }
+            } else {
+                if ($target_collection->contains($item)) {
+                    continue;
+                }
+            }
+
             $clones[] = clone $item;
         }
 
@@ -177,4 +198,39 @@ trait EntityMergerHelperTrait
 
         return $target;
     }
+
+    /**
+     * Merge the attachments from the target and the other entity.
+     * @param  AttachmentContainingDBElement  $target
+     * @param  AttachmentContainingDBElement  $other
+     * @return object
+     */
+    protected function mergeAttachments(AttachmentContainingDBElement $target, AttachmentContainingDBElement $other): object
+    {
+        return $this->mergeCollections($target, $other, 'attachments', function (Attachment $t, Attachment $o): bool {
+            return $t->getName() === $o->getName()
+                && $t->getAttachmentType() === $o->getAttachmentType()
+                && $t->getPath() === $o->getPath();
+        });
+    }
+
+    /**
+     * Merge the parameters from the target and the other entity.
+     * @param  AbstractStructuralDBElement|Part  $target
+     * @param  AbstractStructuralDBElement|Part  $other
+     * @return object
+     */
+    protected function mergeParameters(AbstractStructuralDBElement|Part $target, AbstractStructuralDBElement|Part $other): object
+    {
+        return $this->mergeCollections($target, $other, 'parameters', function (AbstractParameter $t, AbstractParameter $o): bool {
+            return $t->getName() === $o->getName()
+                && $t->getSymbol() === $o->getSymbol()
+                && $t->getUnit() === $o->getUnit()
+                && $t->getValueMax() === $o->getValueMax()
+                && $t->getValueMin() === $o->getValueMin()
+                && $t->getValueTypical() === $o->getValueTypical()
+                && $t->getValueText() === $o->getValueText()
+                && $t->getGroup() === $o->getGroup();
+        });
+    }
 }
\ No newline at end of file
diff --git a/src/Services/EntityMergers/Mergers/PartMerger.php b/src/Services/EntityMergers/Mergers/PartMerger.php
index 1b31815a..c25d0dc6 100644
--- a/src/Services/EntityMergers/Mergers/PartMerger.php
+++ b/src/Services/EntityMergers/Mergers/PartMerger.php
@@ -24,6 +24,9 @@ declare(strict_types=1);
 namespace App\Services\EntityMergers\Mergers;
 
 use App\Entity\Parts\Part;
+use App\Entity\Parts\PartAssociation;
+use App\Entity\Parts\PartLot;
+use App\Entity\PriceInformations\Orderdetail;
 use Symfony\Component\DependencyInjection\Attribute\Autoconfigure;
 
 #[Autoconfigure(public: true)]
@@ -43,14 +46,77 @@ class PartMerger implements EntityMergerInterface
             throw new \InvalidArgumentException('The target and the other entity must be instances of Part');
         }
 
-        //Merge the fields
+        //Merge basic infos
         $this->useOtherValueIfNotNull($target, $other, 'manufacturer');
+        $this->useOtherValueIfNotNull($target, $other, 'footprint');
+        $this->useOtherValueIfNotNull($target, $other, 'category');
+        $this->useOtherValueIfNotNull($target, $other, 'partUnit');
+
+        //We assume that the higher value is the correct one for minimum instock
+        $this->useLargerValue($target, $other, 'minamount');
+
 
-        $this->mergeCollections($target, $other, 'partLots');
-        $this->mergeCollections($target, $other, 'attachments');
-        $this->mergeCollections($target, $other, 'orderdetails');
-        $this->mergeCollections($target, $other, 'parameters');
 
         return $target;
     }
+
+    private function mergeCollectionFields(Part $target, Part $other, array $context): void
+    {
+        /********************************************************************************
+         * Merge collections
+         ********************************************************************************/
+
+        //Lots from different parts are never considered equal, so we just merge them together
+        $this->mergeCollections($target, $other, 'partLots');
+        $this->mergeAttachments($target, $other);
+        $this->mergeParameters($target, $other);
+
+        $this->mergeCollections($target, $other, 'associated_parts_as_owner', function (PartAssociation $t, PartAssociation $o) {
+            //We compare the translation keys, as it contains info about the type and other type info
+            return $t->getOther() === $o->getOther()
+                && $t->getTypeTranslationKey() === $o->getTypeTranslationKey();
+        });
+
+        $this->mergeCollections($target, $other, 'orderdetails', function (Orderdetail $t, Orderdetail $o) {
+            //First check that the orderdetails infos are equal
+            $tmp = $t->getSupplier() === $o->getSupplier()
+                && $t->getSupplierPartNr() === $o->getSupplierPartNr()
+                && $t->getSupplierProductUrl(false) === $o->getSupplierProductUrl(false);
+
+            if (!$tmp) {
+                return false;
+            }
+
+            //Check if the pricedetails are equal
+            $t_pricedetails = $t->getPricedetails();
+            $o_pricedetails = $o->getPricedetails();
+            //Ensure that both pricedetails have the same length
+            if (count($t_pricedetails) !== count($o_pricedetails)) {
+                return false;
+            }
+
+            //Check if all pricedetails are equal
+            for ($n=0, $nMax = count($t_pricedetails); $n< $nMax; $n++) {
+                $t_price = $t_pricedetails->get($n);
+                $o_price = $o_pricedetails->get($n);
+
+                if (!$t_price->getPrice()->isEqualTo($o_price->getPrice())
+                    || $t_price->getCurrency() !== $o_price->getCurrency()
+                    || $t_price->getPriceRelatedQuantity() !== $o_price->getPriceRelatedQuantity()
+                    || $t_price->getMinDiscountQuantity() !== $o_price->getMinDiscountQuantity()
+                ) {
+                    return false;
+                }
+            }
+
+            //If all pricedetails are equal, the orderdetails are equal
+            return true;
+        });
+        //The pricedetails are not correctly assigned to the new orderdetails, so fix that
+        foreach ($target->getOrderdetails() as $orderdetail) {
+            foreach ($orderdetail->getPricedetails() as $pricedetail) {
+                $pricedetail->setOrderdetail($orderdetail);
+            }
+        }
+    }
 }
\ No newline at end of file