Call to undefined method stdClass::update()

Can someone explain to me why this error happen. Below is my code.

public function update(Request $request) //14
{
$searchBarcodeID = $request->label_ID;
$edit_1 = IncomingGetweight::where('label_ID', $searchBarcodeID)->first();
$edit_2 = InprocessGetWeight::where('label_ID', $searchBarcodeID)->first();
$edit_3 = WireGetweight::where('label_ID', $searchBarcodeID)->first();
$edit_4 = InternalscrapGetWeight::where('label_ID', $searchBarcodeID)->first();
$edit_5 = Baler::where('label_ID', $searchBarcodeID)->first();
$edit_6 = ReturnGetweight::where('label_ID', $searchBarcodeID)->first();
$edit_7 = SearchBarcode::where('label_ID', $searchBarcodeID)->first();


// Update each database column with the data submitted from the edit form

$edit_1->PO = $request->PO;
$edit_1->PO_line = $request->PO_line;
$edit_1->invoice = $request->invoice;
$edit_1->label_ID = $request->label_ID;
$edit_1->brand = $request->brand;
$edit_1->date_received = $request->date_received;

$edit_2->invoice = $request->invoice;
$edit_2->label_ID = $request->label_ID;
$edit_2->part_no = $request->part_no;
$edit_2->description = $request->description;
$edit_2->date_received = $request->date_received;

$edit_3->invoice = $request->invoice;
$edit_3->label_ID = $request->label_ID;
$edit_3->part_no = $request->part_no;
$edit_3->work_order = $request->work_order;
$edit_3->status = $request->status;
$edit_3->date_received = $request->date_received;

$edit_4->invoice = $request->invoice;
$edit_4->label_ID = $request->label_ID;
$edit_4->part_no = $request->part_no;
$edit_4->work_order = $request->work_order;
$edit_4->date_received = $request->date_received;

$edit_5->invoice = $request->invoice;
$edit_5->label_ID = $request->label_ID;
$edit_5->part_no = $request->part_no;
$edit_5->work_order = $request->work_order;
$edit_5->date_received = $request->date_received;

$edit_6->invoice = $request->invoice;
$edit_6->label_ID = $request->label_ID;
$edit_6->part_no = $request->part_no;
$edit_6->type = $request->type;
$edit_6->sales_order = $request->sales_order;
$edit_6->sales_order_line = $request->sales_order_line;
$edit_6->date_received = $request->date_received;


$edit_7->PO = $request->PO;
$edit_7->PO_line = $request->PO_line;
$edit_7->invoice = $request->invoice;
$edit_7->label_ID = $request->label_ID;
$edit_7->brand = $request->brand;
$edit_7->part_no = $request->part_no;
$edit_7->description = $request->description;
$edit_7->work_order = $request->work_order;
$edit_7->type = $request->type;
$edit_7->sales_order = $request->sales_order;
$edit_7->sales_order_line = $request->sales_order_line;
$edit_7->date_received = $request->date_received;

$edit_1->update();
$edit_2->update();
$edit_3->update();
$edit_4->update();
$edit_5->update();
$edit_6->update();
$edit_7->update();

return redirect()->route('frontend.praiBarcode.reweight_search')->withFlashSuccess('Barcode record updated successfully!'); 
}